Steerable intra-luminal medical device

ABSTRACT

The disclosure provides a flexible, narrow medical device (such as a micro-catheter or a guidewire) that is controllably moved and steered through lumens of a body. The medical device may include an electrically-actuatable bendable portion at a distal end, which may be provided by a polymer electrolyte layer, electrodes distributed about the polymer electrolyte layer, and electrical conduits coupled to the electrodes, such that the polymer electrolyte layer deforms asymmetrically in response to an electrical signal through one or more conduits. The disclosure further includes a controller for moving the device into and out of bodily lumens and for applying the electrical signal for steering the device. The device further includes methods of preparing the polymer electrolyte layer in tubular shape.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No. 15/562,690filed on Sep. 28, 2017, which is a 371 of International No.PCT/US2017/016513, filed Feb. 3, 2017, and claims the benefit of U.S.Provisional Patent Application No. 62/292,064, filed Feb. 5, 2016, whichare incorporated by reference in their entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable

BACKGROUND Field

The invention relates to a steerable intraluminal medical device and,more particularly, to a flexible, narrow medical device (such as amicro-catheter or a guidewire) introduced into and controllably movedthrough lumens of a body. The medical device may include anelectrically-actuatable bendable portion at a distal, leading end thatcan be selectively manipulated for steering the medical device to atargeted anatomical location within a body.

Description of the Related Art

Intraluminal medical devices have various structures depending on thelocation within the body and the methods of treatment using the devices.Intraluminal devices generally include of a very slender and flexibletube that can be inserted into and guided through a lumen such as anartery or a vein, or a bodily passageway such as a throat, a urethra, abodily orifice or some other anatomical passage. Examples of suchmedical devices include syringes, endoscopes, catheters andmicro-catheters, guide wires and other surgical instruments.

Some medical devices have a portion for being introduced into a bodythat generally comprises a flexible material that is easily bent byapplication of external force. In some medical devices, a distal,leading end (usually inserted first) may be selectively bent in adesired direction through manipulation of a steering mechanism by theuser. The medical device can be inserted into a targeted lumen or bodilypassage and moved to dispose a distal end of the medical device at adesired location in the body.

Surgical techniques for inserting and/or guiding a medical device intoand/or through a lumen or passage in a body have been proposed inresponse to the rise in demand for minimally invasive surgicaltechniques. Many surgical techniques offer poor directional control orcumbersome manipulative components.

SUMMARY

Embodiments of the steerable intraluminal medical device provideimproved steering control and intra-body positioning of an actuationpart (e.g., a micro-catheter or a guidewire) of a medical device whereinthe actuation part is adapted to be introduced into a lumen or a bodilypassage of a body and manipulated while being extended for movement intoand through the lumen and/or bodily passage to dispose a distal end ofthe actuation part of the medical device at a desired anatomicallocation within the body. Embodiments of the medical device provide moreprecise control of movement and positioning of one or more manipulatablemicrosurgical components disposed at a distal, leading end of theactuation part of the medical device for performing a surgical procedureor other medical operation at the desired location within the body.

One embodiment of a medical device having an actuation part (e.g., amicro-catheter or a guidewire) for being moved into and/or through alumen or a bodily passage comprises a slender, elongate and flexibleportion having a distal end and a proximal end, an ionic electroactivepolymer actuator comprising a polymer electrolyte layer disposedadjacent to the distal end of the elongate and flexible portion. Theionic electroactive polymer actuator, as will be discussed in greaterdetail below, is an actuator comprising a polymer electrolyte layer inwhich cations are free to migrate in response to an imposed electricalfield. The electrical field is provided through energization of aplurality of angularly distributed electrodes disposed on the polymerelectrolyte layer. The plurality of angularly distributed electrodes areone of embedded in, deposited on and secured against at least a portionof an exterior wall of the polymer electrolyte layer. Each of theplurality of electrodes may be connected to a source of electricalcurrent through one or more electrically-conductive conduit such as, forexample, a metal wire, being surrounded with the outer member and havinga proximal end coupled to the source of electrical current and a distalend coupled to the electrode. Selective electrical energization of oneor more of the plurality of electrodes causes the polymer electrolytelayer to deform as a result of contraction along a side or portion ofthe polymer electrolyte layer and/or swelling along a side or portion ofthe polymer electrolyte layer. It will be understood that cations withinthe polymer electrolyte layer will migrate towards an energized andanodic electrode, and away from an energized and cathodic electrode,while remaining within the matrix of the polymer electrolyte layer. Thiscauses a portion adjacent to an energized anodic electrode to swell anda portion adjacent to an energized and cathodic electrode to contract,thereby causing the polymer electrolyte layer to bend. It will beunderstood that coordinated control of electrical signals delivered tothe electrodes through electrically-conductive conduits can producebending in an intended direction. In some embodiments, the plurality ofelectrodes may be further electrically connected to a sensing member tosense changes in the electrical signal at each of the plurality ofelectrodes. Accordingly, the sensing member may detect whether the ionicelectroactive polymer actuator deformed or not.

In one embodiment of the medical device, the ionic electroactive polymeractuator may comprise a plurality of angularly distributed electrodesequi-angularly distributed about the exterior wall of the polymerelectrolyte layer. In one embodiment of the medical device, the ionicelectroactive polymer actuator may be included in a bendable portion atthe distal end of an actuation part (e.g., a micro-catheter or aguidewire) of the medical device. For example, but not by way oflimitation, the bendable portion of the medical device may, in oneembodiment, comprise three angularly-distributed electrodes that areseparated, at their centerlines, one from the others by about 120degrees (2.094 radians). As another example, but not by way oflimitation, the bendable portion of the medical device may compriseeight angularly-distributed electrodes that are separated, at theircenterlines, by about 45 degrees (0.785 radians). It will be understoodthat each of the plurality of electrodes occupies a circumferential spanabout the exterior wall of the polymer electrolyte layer, and that the“angular separation” may therefore be stated in terms of the centerlinesof the electrodes instead of in terms of the adjacent edges of theelectrodes, which will be much closer to the adjacent edge of theadjacent electrode. In some embodiments of the medical device, theelectrodes are spaced in a manner to provide a substantial gapintermediate adjacent electrodes.

In a bendable portion at the distal end of an actuation part of anotherembodiment of the medical device, the ionic electroactive polymeractuator is provided in which the plurality of electrodescircumferentially distributed about the exterior wall of a polymerelectrolyte layer are, along with at least a portion of an adjacentinner member of the elongate and flexible portion, surrounded by anouter member, coating, sheath or other barrier having a bore in which atleast a portion of the plurality of electrodes and at least a portion ofthe polymer electrolyte layer surrounded by the electrodes are togetherdisposed. The outer member, or an exterior wall of the outer member, maycomprise a low-friction, hydrophilic and/or lubricious material thatpromotes smooth sliding engagement between the elongate and flexibleportion of the medical device and an interior wall of a lumen or abodily passage into which the actuation part of the medical device isintroduced and through which the elongate and flexible portion of themedical device is extended to position a distal end of the actuationpart of the medical device at a targeted location within a body. Theouter member may comprise one or more materials including, but notlimited to, nylon, polyurethane and/or a thermoplastic elastomer suchas, for example, PEBAX®, a polyether block amide material available fromArkema France Corporation of Colombes, France.

In one embodiment of the medical device, the plurality ofelectrically-conductive conduits that conduct electrical signals from asource of electricity to one or more of the plurality of electrodes toaffect bending of the polymer electrolyte layer comprise a noble metalfor superior chemical stability and corrosion resistance. For example,but not by way of limitation, the electrically-conductive conduits thatdeliver current to selected electrodes to actuate the polymerelectrolyte layer may comprise highly conductive platinum, a platinumalloy, silver or a silver alloy, or they may comprise gold or a goldalloy which, in addition to being chemically stable and corrosionresistant, is malleable and can be advantageously formed into veryslender electrically-conductive conduits with very low resistance tobending.

In a relaxed or un-energized state, the polymer electrolyte layer of theionic electroactive polymer actuator remains in its original form.

One embodiment of the elongate and flexible portion of the medicaldevice includes an elongate, flexible inner member having a distal end,a proximal end, a radially interior bore with an axis, and a radiallyexterior wall, at least one ionic electroactive polymer actuatorcomprising polymer electrolyte layer having a bore, the polymerelectrolyte layer secured adjacent to the distal end of the inner memberwith the bore of the polymer electrolyte layer aligned with the bore ofthe inner member, a plurality of electrodes circumferentiallydistributed about the at least one polymer electrolyte layer, and aplurality of electrically-conductive conduits, each having a proximalend and a distal end coupled to at least one of the plurality ofelectrodes, and an elongate and flexible center wire having a proximalend, a distal end and a diameter therebetween that is smaller than thediameter of the bore of the inner member to enable the distal end of thecenter wire to be introduced into the bore of the inner member and tothen be pushed through the bore of the inner member to position thedistal end of the center wire adjacent to the distal end of the innermember, a radially compressed and resilient spring member coupled to thedistal end of the center wire, the compressed spring member sized, in anuncompressed or expanded configuration, for exceeding the diameter ofthe bore of the inner member in an expanded configuration and forfitting within and being positioned in the bore of the inner member bythe center wire in a compressed configuration, wherein the polymerelectrolyte layer of the ionic electroactive polymer actuator deformsasymmetrically in response to the application of one or more electricalsignals conducted from a source of electrical current (which may befurther coupled to the proximal end of each electrically-conductiveconduit) through at least one of the plurality ofelectrically-conductive conduits to at least one of the plurality ofelectrodes coupled to a distal end of the at least one of the pluralityof electrically-conducting electrodes, and wherein the center wire canbe used to position the spring member immediately adjacent to the distalend of the inner member with the inner member disposed within orimmediately adjacent to an obstruction in a lumen into which the innermember is introduced, and wherein the spring member can be expanded fromthe compressed configuration to the expanded configuration to engage andgrip the obstruction in the lumen by retracting the inner member whilemaintaining the center wire stationary relative to the inner member tocause the compressed spring member to be removed from the bore of theinner member and released from the radially compressed configuration tothe expanded configuration within the obstruction to be gripped by theexpanded spring member, thereby allowing the obstruction to be retrievedfrom the lumen by retrieving the center wire and the inner membertogether from the lumen. In one embodiment, the spring member is a coilspring having a plurality of coils aligned in a series. In anotherembodiment, the spring member includes a plurality of corrugated orsinusoidally shaped wires, each wire coupled at the apexes of the wavesor peaks to the apexes of the waves or peaks of an adjacent wire to forma generally tubular or cylindrically shaped spring assembly. It will beunderstood that expandable spring elements of this type generallyelongate as they radially expand from a radially compressedconfiguration to a radially expanded configuration.

One embodiment of the medical device includes an electrically insulatinglayer disposed within the bendable portion of the medical device. Thisinsulating layer provides a flexible insulating boundary layer thatcontains but conforms to the polymer electrolyte layer as it deforms inresponse to an electrical field imposed by electrical signals conductedto the surrounding electrodes to provide advantageous steering of themedical device as it is positioned within a lumen or bodily passage.

The polymer electrolyte layer comprises an electrolyte (e.g., ionicliquid, but not limited to this) and a polymer selected from the groupconsisting of fluoropolymers and intrinsically conducting polymers. Oneembodiment of a method of preparing a tubular polymer electrolyte layerfor use in providing an ionic electroactive polymer actuator in abendable portion of a medical device comprises: providing a liquiddispersion of a base material selected from the group consisting offluoropolymers and intrinsically conducting polymers, disposing theliquid dispersion on a substrate, curing the liquid dispersion of theselected base material to form a polymer film on the substrate,providing a mandrel, wrapping the polymer film onto the mandrel, andproviding a heat-shrink tube, covering a portion of the mandrel wrappedin the polymer film with the heat shrink tube, and heating theheat-shrink tube to cause reflow the polymer film to form a tubularpolymer electrolyte layer.

The polymer electrolyte layer may comprise, for example, but not by wayof limitation, a polymer membrane containing a electrolyte (e.g.,solvent such as, water or an ionic liquid). Alternately, the polymerelectrolyte may comprise a porous polyvinylidene fluoride orpolyvinylidene difluoride, a highly non-reactive thermoplasticfluoropolymer produced by the polymerization of vinylidene difluoride,and containing ionic liquid or salt water. Alternately, the polymerelectrolyte may comprise a gel formed by polyvinylidene fluoride orpolyvinylidene difluoride, propylene carbonate and an ionic liquid.

In one embodiment of the method of preparing a tubular polymerelectrolyte layer for use in providing an ionic electroactive polymeractuator in a bendable portion of a medical device, the materialselected to use in forming the base material comprising fluoropolymersand/or intrinsically conducting polymers. For example, the material maybe, one of Nafion® and Flemion®, which are perfluorinated ionomers. Inanother embodiment of the method, the material selected to use informing the base material comprising one of polyvinylidene difluoride(PVDF) and/or one of a co-polymer thereof, for example, one ofpolyvinylidene difluoride-co-chlorotrifluoroethylene (P(VDF-CTFE)) andpolyvinylidene fluoride-co-hexafluoropropylene (P(VDF-HFP)), which arefluoropolymers. In yet another embodiment of the method, the materialselected to use in forming the base material comprising an intrinsicallyconductive polymer (ICP), for example, one of polyaniline (PAN I),polypyrrole (Ppy), poly(3,4-ethylenedioxythiophene) (PEDOT) andpoly(p-phenylene sulfide)(PPS). In yet another embodiment of the methodof preparing a tubular polymer electrolyte layer, the material selectedto use in forming the base material comprises a combination of two ormore of the above listed and described base materials.

One embodiment of the method of preparing a tubular polymer electrolytelayer includes the step of dissolving the base material in a volatilesolvent to form the liquid dispersion. The volatile solvents that may beused for this step include, but are not limited to, acetates, alcohol,chloroform, ether, aliphatic hydrocarbons, aromatic hydrocarbons,chlorinated hydrocarbons and ketones.

One embodiment of the method of preparing a tubular polymer electrolytelayer includes the step of disposing the liquid dispersion of theselected base material onto a solid substrate comprising one ofpolytetrafluoroethylene (PTFE) or glass. However, other solid substrateshaving non-stick surfaces may be substituted.

A first example of an embodiment of the method of preparing a tubularpolymer electrolyte layer includes preparing a liquid dispersion ofNafion® in 10 to 20 wt. % alcohol, disposing the liquid dispersion on aflat PTFE substrate using a doctors' blade method to form a thickness of15-25 pm, curing the liquid dispersion on the substrate at 68° F. (20°C.), removing volatile solvents by thermal treatment at 176 to 248° F.(80 to 120° C.), rolling the resulting Nafion® film around a stainlesssteel mandrel rod having an outside diameter of 0.025″ (0.635 mm) bymanually rotating the mandrel while translating the mandrel across thesubstrate to roll-up the Nafion® film into a tubular shape having aninterior diameter and a wall thickness.

The resulting interior diameter and wall thickness of the resultingpolymer tubing depend on the mandrel size, the thickness of the Nafion®film and the number of times the mandrel can be wrapped with the Nafion®film during the rolling step. The mandrel with the rolled Nafion® filmis fitted into a fluorinated ethylene-propylene (FEP) heat-shrink sleeveand then heated at the recovery temperature of the heat-shrink material392 to 446° F. (200 to 230° C.). During heating, the layers of therolled Nafion® film are reflowed into a single homogenous polymer layer.After cooling and removing the heat-shrink tube and mandrel, a Nafion®tube having a homogenous morphology without traces of rolled layers. Thetolerance of the wall thickness of the prepared Nafion tube is similarto commercially extruded Nafion tubing (+1-10%) but is prepared withoutthe need for commercial extrusion equipment that can require a largeamount of space and equipment.

A second example of an embodiment of the method is to prepare a PVDFtube, including the steps of providing a plurality of Poly[(vinylidenedifluoride)-co-(chlorotrifluoroethylene)] (P(VDF-CTFE)) pellets,dissolving the pellets in acetone by heating and stirring the pellets inthe acetone at about 122° F. (50° C.) for 4 hours. The prepareddispersion is disposed on a flat PTFE substrate using the doctors'blade. The substrate and dispersion disposed thereon are cured at 68° F.(20° C.) for 30 minutes and the resulting film is then peeled from thePTFE substrate. The prepared P(VDF-CTFE) film is vacuum dried at 172° F.(80° C.) to remove the residual solvent. The formed PVDF film of 15-25pm in thickness is rolled around a stainless steel mandrel rod having anouter diameter of 0.025 inches (0.635 mm) by manually rotating themandrel and translating the mandrel across the film. The mandrel withthe rolled PVDF film thereon is fitted into a heat-shrink polymer tube(e.g., fluorinated ethylene-propylene (FEP)) and heated at a recoverytemperature of the heat-shrink material 392 to 446° F. (200 to 230° C.).The heating causes the layers of the rolled PVDF film to reflow into asingle homogenous polymer tube wall. The heat-shrink tube is removedafter cooling from the mandrel to remove the PVDF tube.

To further prepare an ionic electroactive polymer actuator, the preparedNafion tube or PVDF tube may be further processed to deposit metalelectrodes thereon (e.g., platinum or gold electrodes) usingconventional methods such as an electrochemical process. Then, wires(e.g., gold wires) can be further integrated and embedded into theprepared metal electrodes using conducting paste or laser welding toserve as electrically-conductive conduits. Alternatively, in oneembodiment, the prepared Nafion tube or PVDF tube may be furtherprocessed to deposit carbon-based electrodes using a new reflow methodprovided and explained in further detail below for use in providing atubular ionic electroactive polymer actuator. Then, wires (such as goldwires) can be further integrated and embedded into the preparedcarbon-based electrodes during the reflow method to serve aselectrically-conductive conduits.

In one embodiment, a method of preparing a tubular ionic electroactivepolymer actuator of a medical device by disposing carbon-basedelectrodes on a polymer electrolyte layer with a heat-shrink tube usingreflow process is provided. The method may comprise: providing a polymerelectrolyte layer having a radially exterior wall, providing a mixtureof a carbon-based conductive powder in a volatile solvent, providing aplurality of electrically-conductive conduits, each having a proximalend and a distal end, disposing the mixture on the exterior wall of thepolymer electrolyte layer to form a carbon electrode layer thereon,contacting the distal end of each electrically-conductive conduit to thecarbon electrode layer, providing a heat-shrink tube, covering thepolymer electrolyte layer and the carbon electrode layer thereon withthe heat-shrink tube, and heating the heat-shrink tube to cause reflowof the polymer electrolyte layer to form the ionic electroactive polymeractuator. In another embodiment of the method of preparing a tubularionic electroactive polymer actuator of a medical device, the polymerelectrolyte layer may be further impregnated with an electrolyte. Forexample, the electrolyte may be an ionic liquid including, but notlimited to, 1-ethyl-3-methylimidazolium tetrafluoroborate (EMI-BF4),1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMI-TFSI)or the combination thereof. In yet another embodiment of the method ofpreparing a tubular ionic electroactive polymer actuator of a medicaldevice, a portion of the carbon electrode layer is further covered withone or more metal layer to increase the electrical conductivity of theobtained carbon-based electrodes. The metal layer herein may be, forexample, but are not limited to a gold layer, a platinum layer or thecombination thereof.

In other embodiment of the method of preparing a tubular ionicelectroactive polymer actuator of a medical device, the carbon-basedconductive powder may be carbide-derived carbon, carbon nanotube, carbonaerogel, graphene, or the combination thereof. In some embodiments, thecarbon-based conductive powder may optionally comprise fillers such astransition metal oxide powder, metal powder or the combination thereof.In some embodiments, the mixture of a carbon-based conductive powder isdisposed on the exterior surface of the polymer electrolyte layer usingbrush coating or spray coating. In other embodiments, the carbonelectrode layer is further micro-machined to form a plurality ofelectrodes after heating the heat-shrink tube.

In one embodiment of the medical device, an electrical controller isprovided for controlling bending of the bendable portion by applyingelectrical signals to an ionic electroactive polymer actuator in thebendable portion. The electrical controller may be provided at theproximal end of the elongate, flexible portion and electricallyconnected to the electrically-conductive conduits for selectivelycontrolling the electrical charges carried by theelectrically-conducting conduits and imparted to the plurality ofelectrodes to manipulate the at least one ionic electroactive polymeractuator of the medical device. In another embodiment, the electricalcontroller may be further instructed by a master controller. The mastercontroller may comprise a manipulatable control member for inputting thebending control signals to the at least one ionic electroactive polymeractuator for providing two degrees of freedom of bending through theelectrical controller.

To steerably control the medical device, in some embodiments, themedical device further comprises a driving assembly for moving themedical device (e.g., the flexible, elongated member portion)lengthwise. The drive assembly includes: a first rotary drive memberwith a gripping surface, an adjacent second rotary drive member with agripping surface disposed proximal to the gripping surface of the firstrotary drive member, and at least one electrically powered motor coupledto controllably rotate at least one of the first rotary drive member andthe second rotary drive member and wherein, the medical device isdisposed intermediate and engaged by the gripping surface of the firstrotary drive member and the gripping surface of the adjacent secondrotary drive member so that rotation of one of the first rotary drivemember and the second rotary drive member axially moves the medicaldevice. In one embodiment of steerably controlling the medical device,clockwise rotation of the first rotary drive member and counterclockwiserotation of the adjacent second rotary drive member moves the medicaldevice in a first direction; and counterclockwise rotation of the firstrotary drive member and clockwise rotation of the adjacent second rotarydrive member moves the medical device in a second direction opposite tothe first direction. In another embodiment, the driving assembly may bealso further instructed by the master controller that comprise amanipulatable control member for inputting advance and retract controlsignals to the drive assembly for providing one degree of freedom oftranslation. In some embodiments, the master controller may provide thebending control signals as well as the advance and retract signals.

In one embodiment of steerably controlling the medical device, themedical device may further comprise a case that includes: a firstportion having a sealed interior portion containing the first rotarydrive member, the second rotary drive member, a proximal port throughwhich the medical device passes, a distal port through which the medicaldevice passes, and an interior cavity for storing windings of themedical device; and wherein the case further includes a second portionsupporting the motor. In another embodiment, the second portion of thecase and the first portion of the case are adapted for being coupled oneto the other to operatively engage the motor with at least one of thefirst rotary member and the second rotary member. In other embodiments,the first portion may be disposable, for example, after use andcontamination by bodily fluids contacted by the medical device.

In one embodiment, for remotely controlling/positioning the medicaldevice when being introduced into and moving through a lumen of a humanbody, the medical device may further comprise: a transmitter coupled tothe master controller for transmitting a signal corresponding to themanipulation of the master controller; and a receiver electricallyconnected to the drive assembly and the electrical controller forreceiving the signal transmitted by the transmitter to the driveassembly and/or the electrical controller to correspond to themanipulation of the controller.

BRIEF DESCRIPTION OF THE DRAWINGS

The appended illustrative drawings provide a further understanding ofembodiments and are incorporated into and constitute a part of thisapplication and, together with the written description, serve to explainthe present invention. The appended drawings are briefly described asfollows.

FIG. 1 is a perspective view showing one embodiment of a case forcontaining components used to controllably extend and retract anextendable actuation part of a medical device.

FIG. 2 is a perspective view of the elongate, flexible portion and abendable portion disposed at the distal end of the actuation part of theembodiment of the medical device of FIG. 1 .

FIG. 3 is the perspective view of the distal, bendable portion at thedistal end of the actuation part of FIG. 2 illustrating the bendingmode.

FIG. 4A is a cross-sectional view of the distal end of the bendableportion of FIGS. 2 and 3 illustrating a first selected set of fourelectrical signals applied to the four angularly-distributed electrodesdisposed about the polymer electrolyte layer. The arrow indicates thedirection of bend produced by the application of the illustrated set ofelectrical signals to the four individual electrodes.

FIG. 4B is the cross-sectional view of the distal end of the bendableportion of FIG. 4A revealing a second selected set of four electricalsignals applied to the angularly distributed electrodes disposed aboutthe polymer electrolyte layer. The arrow indicates the direction of bendproduced by the application of the illustrated electrical signals to thefour individual electrodes.

FIG. 5 is a perspective view of an alternative embodiment of a bendableportion and an elongate, flexible portion of an actuation part of amedical device of one embodiment having a plurality of individualelectrodes separated both longitudinally and circumferentially. Eachindividual electrode is connected to an electrically-conductive conduitwhich provides an electrical signal to the electrode.

FIG. 6 is a block diagram schematically illustrating the systems andcomponents that are used to use and control an embodiment of the medicaldevice of FIGS. 1-4B.

FIG. 7 is a lengthwise sectional view of a distal end of an extendableand steerable actuation part of an embodiment of a medical device,including a distal, bendable portion and an elongate, flexible portion.

FIG. 8A is a perspective view of an upper case portion of the case ofthe embodiment of the medical device of FIG. 1 with the upper caseportion of the case indicated in dotted lines to better reveal thecomponents disposed therein.

FIG. 8B is a perspective view of a lower case portion of the case of theembodiment of the medical device of FIG. 1 with the lower case portionof the case indicated in dotted lines to better reveal the componentsdisposed therein.

FIG. 9 is an elevational sectional view of an embodiment of a medicaldevice provided by assembling of the upper case portion and the lowercase portion of FIGS. 8A and 8B. The medical device is in wirelesscommunication with a master controller.

FIG. 10 is a flowchart illustrating the steps of a method of performingsurgery by use of the embodiment of an embodiment of the medical deviceillustrated in FIGS. 7A, 7B and 8 .

FIG. 11 is a flowchart illustrating a method of imparting a bend to abendable portion at the distal end of an actuation part of an embodimentof the medical device.

FIG. 12 is a modification of the block diagram of FIG. 6 illustratingthe control system structure for an alternative embodiment of themedical device including an actuation part and a case.

FIG. 13 is a graph illustrating variance over time in an electricalsignal applied to an electrode disposed with other electrodes tosurround a polymer electrolyte layer of a bendable portion of anactuation part of an embodiment of a medical device.

FIG. 14 is a cross-sectional view illustrating an alternativedistribution of individual electrodes in recesses formed into a polymerelectrolyte layer of a bendable portion of an actuation part of anembodiment of a medical device.

FIG. 15 is a cross-sectional view of an alternative configuration for abendable portion of an actuation part of the medical device.

FIG. 16 is a flowchart illustrating a method of using a sensing memberto monitor the performance of an embodiment of a medical device and ofdetermining the impact of an external force on the performance of theembodiment of the medical device.

FIG. 17 illustrates an alternate embodiment of the case portion of themedical device for controllably advancing and withdrawing the actuationpart of the medical device.

FIG. 18 is a perspective view of an alternative case with a guide barrelremoved to reveal the positions of the components therein.

FIG. 19 is perspective view of an elongate, flexible portion of anactuation part of a medical device with a section of an outer memberremoved to reveal details of the components of the actuation part ofthis embodiment of the medical device.

FIG. 20 is cross-sectional view of an embodiment of an elongate,flexible portion of an actuation part of a medical device. The elongate,flexible portion may include electrically-conductive conduits and ametal reinforcing mesh or braid.

FIG. 21 is a cross-sectional view of an alternative embodiment of theelongate, flexible portion of an actuation part of the medical device inwhich each of the electrically-conductive conduits are embedded within alumen structure and each electrically-conductive conduit and its lumenstructure are together encased within the material of the outer member.

FIG. 22 a cross-sectional view of an alternative embodiment of theelongate, flexible portion of an actuation part of the medical device inwhich each of the electrically-conductive conduits are electricallyinsulated encased within a single, tubular insulation member that issurrounded by the outer member.

FIG. 23 is a modification of the block diagrams of FIGS. 6 and 12illustrating a control system for an alternative embodiment of themedical device including an actuation part and a case.

FIG. 24 is an enlarged view of a portion of FIG. 5 showing anarrangement of four electrically-conductive conduits adhered to anexterior surface of the inner member of the elongate, flexible portionof a medical device.

FIG. 25 is an enlarged perspective view of an ionic electroactivepolymer actuator that is included in the bendable portion of anactuation part of an alternate embodiment of the medical device.

FIG. 26 is an illustration of a distal end of an actuation part of anembodiment of a medical device with a spring member, in a radiallycompressed configuration, coupled to a center wire advanced through thebore of the actuation part to dispose the spring element adjacent to anobstruction in a lumen.

FIG. 27 is an illustration of the spring member in an expandedconfiguration, obtained by withdrawal of the bore of the actuation partwhile holding the center wire stationary, to expand and grip theobstruction for removal with the actuation part and the center wire.

FIG. 28 is an alternative embodiment of the spring member that can beused to implement the method illustrated by FIGS. 26 and 27 .

FIG. 29 is a perspective view of the elongate, flexible portion and abendable portion disposed at the distal end of the actuation part ofanother embodiment of the medical device of FIG. 1 .

FIG. 30 is the perspective view of the distal, bendable portion at thedistal end of the actuation part of FIG. 29 illustrating the bendingmode.

DETAILED DESCRIPTION

Medical devices such as catheters or guidewires may be sufficientlyslender for being inserted into a lumen such as an artery, a vein, athroat, an ear canal, a nasal passage, a urethra or any of a number ofother lumens or bodily passages. These slender catheters (also referredto as micro-catheters) and guidewires, enable physicians to performnon-invasive surgery requiring a substantially shortened recovery periodby preventing the need for cutting a subject or a patient to providelocal access for performing a surgical procedure or medical operation.As used herein, the terms “subject” or “patient” refer to the recipientof a medical intervention with the device. In certain aspects, thepatient is a human patient. In other aspects, the patient is acompanion, sporting, domestic or livestock animal.

The following paragraphs describe certain embodiments of medical devicesthat can be used to perform or to enable the performance of surgicaloperations using the same, and methods that can be used to enable thepreparation of such medical devices for same. It will be understood thatother embodiments of medical devices and methods are within the scope ofthe claims appended herein below, and the illustration of suchembodiments is not limiting of the present invention.

FIG. 1 is a perspective view showing one embodiment of a medical device10 having a case 200 and an actuation part 100. The medical device 10 ofFIG. 1 includes an upper case portion 210 and a lower case portion 220of the case 200, the medical device 10 further including a flexible,elongate and slender actuation part 100 that comprises an elongate,flexible portion 101 to be extendable from the upper case portion 210 ofthe case 200 and a bendable portion 110 (FIG. 2 ) disposed at the distalend 102. The elongate, flexible portion 101 comprises an inner member120 (FIG. 2 ) that is sufficiently slender to can be inserted into alumen (not shown) of a body (not shown). Also the inner member 120 issufficiently flexible and substantially axially incompressible so thatit can be advanced through a lumen having a winding pathway by pushingor driving the elongate, flexible portion 101 of the actuation part 100forward after a distal end 102 of the actuation part 100 is introducedinto the lumen of the body (not shown). The actuation part 100 furtherincludes a proximal end 109. The medical device 10 may be amicro-catheter having a bendable portion 110 that comprise an interiorbore 140 (FIG. 2 ) to facilitate the movement of an elongate structure(not shown). In one embodiment, the elongate structure may be fed fromthe proximal end 109 through the interior bore 140 (FIG. 2 ) to andthrough the distal end 102 of the actuation part 100 of the medicaldevice 10. Alternatively, the medical device 10 may be a guidewirehaving a bendable portion 110 without an interior bore 140 (e.g., FIG.29 ).

Optionally, the proximal end 109 of the actuation part 100 may include afastener such as, for example, threads 113, for use in securing a matingsocket or other structure to the proximal end 109 of the actuation part100. Optionally, the upper case portion imparting a forward directionalaspect to a distal portion 102 of the actuation part 100 that extendsbeyond the case 200.

FIG. 2 is a perspective view of the elongate, flexible portion 101 and abendable portion 110 disposed at the distal end 102 of the actuationpart 100 of the embodiment of the medical device 10 (e.g., amicro-catheter) of FIG. 1 . The bendable portion 110 of the actuationpart 100 includes an ionic electroactive polymer actuator comprising apolymer electrolyte layer 139 disposed adjacent to the inner member 120of the elongate, flexible portion 101 and centrally to anangularly-distributed plurality of energizable electrodes 112. Each ofthe plurality of electrodes 112 that surrounds the exterior wall 137 ofthe polymer electrolyte layer 139 is connected to a distal end 131 of anelectrically-conductive conduit 130 through which an electrical signalor current may be supplied to the connected electrode 112. The polymerelectrolyte layer 139 includes a bore 140 through which other elongatestructures may be inserted to position, control and/or actuate aneffector or surgical tool or instrument disposed at the distal end ofthe elongate structure. The bore 140 of the polymer electrolyte layer139 is, in a relaxed or de-energized condition, centered about an axis141. The bendable portion 110 of FIG. 2 is illustrated in the straightmode. The bendable portion 110 can be selectively and controllablydeformed to a bent mode by selective energization of one or more of theplurality of electrodes 112, as will be explained in further detailbelow.

In one embodiment of the medical device 10, the ionic electroactivepolymer actuator of the bendable portion 110 of FIG. 2 is an ionicpolymer-metal composite (IPMC) actuator. In one embodiment of themedical device 10, the ionic electroactive polymer actuator comprises apolymer electrolyte layer 139 made of a perfluorinated ionomer ofNafion® (Nafion® is available from E. I. DuPont de Nemours and Company)that have superior ion transport properties. Alternately, otherembodiments of the ionic electroactive polymer actuator of the medicaldevice 10 may include a polymer electrolyte layer 139 that comprises aperfluorinated ionomer such as Aciplex™ (available from Asahi KaseiChemical Corp. of Tokyo, Japan), Flemion® (available from AGC ChemicalAmericas, Inc. of Exton, Pa., USA) or Fumapem® F-series (available fromFumatech BWT GmbH, Bietigheim-Bissingen, Federal Republic of Germany).In a preferred embodiment, the perfluorinated ionomer is Nafion®.

In one embodiment of the medical device 10, the electrically-conductiveconduits 130 may comprise one of platinum, gold, carbon, alloys thereofor a combination thereof. In other embodiments, the material forelectrodes 112 may comprise carbon, such as carbide-derived carbon,carbon nanotubes, a composite of carbide-derived carbon or ionomer, anda composite of carbon nanotube and ionomer. A method according to oneembodiment of disposing the carbon-based electrodes 112 onto the polymerelectrolyte layer 139 will be discussed herein below.

Each of the plurality of electrodes 112 is connected to a distal end 131of an electrically-conductive conduit 130 through which an electricalsignal may be applied to the electrode 112 to which the conduit 130 isconnected, thereby causing metal cations within the polymer electrolytelayer 139 to move in a direction determined by the applied electricalsignal. This cation migration produced by the applied electrical signalcauses the polymer electrolyte layer 139 to swell in the portion of thepolymer electrolyte layer 139 disposed proximal to the anode and to bendor warp in the direction of the remaining unswelled portion. As aresult, the magnitude and the direction of bending deformations of thepolymer electrolyte layer 139 of the ionic electroactive polymeractuator can be controlled by strategically selecting the electrodes 112to energize and by adjusting the electrical signal applied through theelectrically-conductive conduits 130 to the electrodes 112.

As shown in FIG. 2 , the polymer electrolyte layer 139 includes acircular bore 140, and the plurality of electrodes 112 are angularlydistributed about the circumference of the polymer electrolyte layer139.

FIG. 3 is a perspective view of the bendable portion 110 at the distalend 102 of the actuation part 100 of FIG. 2 illustrating the deformed orbending mode. The bendable portion 110 of the actuation part 100 of themedical device 10 is illustrated as having been actuated from thestraight mode shown in FIG. 2 to the deformed or bent mode of FIG. 3through the selective application of electrical signals to selectedelectrodes 112 to deform the polymer electrolyte layer 139. Theenergization of selected electrodes 112 causes the bendable portion 110to be deformed from the straight mode to the bent mode by application ofan external force indicated by arrow 118

Alternately, in the event that the actuation part 100 is observed to bein a deformed mode in the absence of the application of one or moreelectrical signals to one or more of the plurality of the electrodes112, the magnitude of the observed deflection can be used to determinethe magnitude and direction of an external force applied to theactuation part 100 or, alternately, in the event that the application ofa known current to the electrodes 112 fails to produce an anticipateddeformation of the bendable portion 110 of the actuation part 100, thedifference between the anticipated deformation and the actualdeformation (if any) can be used as an indicator of the magnitude of anexternal force applied to the bendable portion 110 at the distal end 102of the actuation part 100 of the medical device 10.

FIG. 4A is a cross-sectional view of the distal end 102 of the bendableportion 110 of the actuation part 100 of FIGS. 2 and 3 illustrating afirst selected set of four electrical signals applied to fourcircumferentially distributed electrodes 112 disposed about the exteriorwall 137 of the polymer electrolyte layer 139. FIG. 4A illustrates theelectrical signals that may be applied to the plurality of angularlydistributed electrodes 112 to impart bending of the bendable portion 110of the actuation part 100 in the direction of the arrow 118. It will beunderstood that the application of a positive charge on the electrodes112 on the left and right sides of the bendable portion 110 of FIG. 4A,in addition application of a positive charge to the electrode 112 at thetop of FIG. 4A, and further in addition to the application of a negativecharge to the electrode 112 at the bottom of FIG. 4A, may result in adifferent amount of deformation than would occur as a result of theapplication of a positive charge on the electrode 112 at the top of FIG.4A with a negative charge imparted to the remaining electrodes 112. Itwill be understood that the user may select the plurality of electricalsignals that produces the deformation desired by the user.

FIG. 4B is the cross-sectional view of the distal end 102 of thebendable portion 110 of the extendable actuation part 100 of FIG. 4Arevealing a second selected set of four electrical signals applied tothe circumferentially distributed electrodes 112 disposed about thepolymer electrolyte layer 139. FIG. 4B illustrates the application of apositive charge to the electrode 112 at the top of the bendable portion110 of FIG. 4B and also to the electrode 112 at the right side of thebendable portion 110 of FIG. 4B, and FIG. 4B further illustrates theapplication of a negative charge to the electrode 112 at the bottom ofFIG. 4B and also to the electrode 112 at the left side of FIG. 4B. Thedeformation of the polymer electrolyte layer 139 resulting from theapplication of these electrical charges is in the direction of the arrow118.

It will be understood from FIGS. 4A and 4B that the distal end 102 ofthe bendable portion 110 of the actuation part 100 of the medical device10 (e.g., a micro-catheter) can be bent in multiple directions and withvarying degrees of deformation or deflection by strategic control of theelectrical charges imparted to each of the individual electrodes 112.Although the embodiment illustrated in FIGS. 4A and 4B illustrates abendable portion 110 including four electrodes 112, it will beunderstood that the bendable portion 110 of the actuation part 100 ofthe medical device 10 may include fewer than four or more than fourelectrodes 112, and such other embodiments will have differingdeflection and deformation directional capacities.

FIG. 5 is a perspective view of an alternative embodiment of a bendableportion 110 of an actuation part 100 of a medical device 10 (e.g., amicro-catheter). FIG. 5 illustrates how the magnitude and direction ofdeflection and deformation of the polymer electrolyte layer 139 may betailored by disposing a plurality of electrodes 112 a, 112 b, 112 c and112 d at varying positions along the length of the bendable portion 110of the actuation part 100. By way of example and not by limitation, thebendable portion 110 of the actuation part 100 of FIG. 5 may includesixteen circumferentially and axially distributed electrodes 112 a, 112b, 112 c and 112 d with the first set of four electrodes 112 a disposedproximal to the distal end 102 of the bendable portion 110 of theactuation part 100, a second set of four electrodes 112 b disposedadjacent to the first set of electrodes 112 a, a third set of fourelectrodes 112 c disposed adjacent to the second set of electrodes 112b, and a fourth set of electrodes 112 d disposed adjacent to the thirdset of electrodes 112 c. Each of the sixteen electrodes 112 a, 112 b,112 c and 112 d (four sets) disposed on the bendable portion 110 of theactuation part 100 of the medical device 10 is connected to one ofsixteen electrically-conductive conduits 130 a, 130 b, 130 c and 130 d,each for delivering an energizing current to the respective electrodes.The embodiment of the bendable portion 110 of the actuation part 100illustrated in FIG. 5 results in enhanced deformation of the bendableportion 110 due to reduced resistance to bending intermediate theaxially-spaced apart sets of electrodes 112

FIG. 6 is a block diagram schematically illustrating the control systemstructure for the embodiment of the medical device 10 of FIGS. 1-4B. Themedical device 10 herein may be a micro-catheter with an interior bore140 (e.g., FIGS. 2-4B) or a guidewire without the interior bore 140(e.g., FIG. 29 ). The medical device 10 includes an actuation part 100adapted for insertion into a lumen or bodily passage and a case 200 witha drive assembly 300 (see FIGS. 8A-9 ) for advancing the elongate,flexible portion 101 and the bendable portion 110 of the actuation part100 into and through a lumen or bodily passage and for selectivelybending the bendable portion 110 at the distal end 102 of the actuationpart 100. FIG. 6 illustrates the control interaction between the case200, which contains both the drive assembly 300 for use in advancing theactuation part 100 into and through the lumen or bodily passage and anelectrical controller 400 for selectively controlling the electricalcharges carried by the electrically-conductive conduits 130 and impartedto the plurality of electrodes 112 to manipulate the bendable portion110 of the actuation part 100 of the medical device 10. The electricalcontroller 400 may comprise a processor (not shown) that calculates thevalues of an electrical signal applied to the electrodes 112, inresponse to a user's input signals from the master controller 500. Themaster controller 500, which may be at a location other than thelocation of the patient, is shown wirelessly, telephonically and/or viathe Internet, communicating with the case 200 of the medical device 10in FIG. 6 . It will be understood that, in one embodiment illustrated inFIG. 6 , the master controller 500 of the medical device 10 may be inthe presence of a surgeon (operator or user) that is remote from thepatient (body) and the medical device 10. In that embodiment, themedical device 10 will include the master controller 500 or,alternately, an embodiment of the medical device 10 may not include amaster controller 500 and may be used by a surgeon who is present in theoperating room along with the patient and with the case 200. The mastercontroller 500 may include, for example, a joystick for enabling theuser to input the bending control signals to the electrodes 112 of thebendable portion 110 for providing two degrees of freedom of bendingthrough the electrical controller 400, and a rolling input, such as, forexample, a track ball or track wheel, for enabling the user to inputadvance and retract control signals to the drive assembly 300 forproviding one degree of freedom of translation.

FIG. 7 is a lengthwise sectional view of an extendable and steerableintraluminal actuation part 100 of an embodiment of a medical device 10(e.g., a micro-catheter), including a distal, bendable portion 110 andan elongate, flexible portion 101.

FIG. 7 reveals the polymer electrolyte layer 139 and a plurality ofsurrounding electrodes 112. Each electrode 112 is electrically coupledto an electrically-conductive conduit 130. The bendable portion 110 isdisposed adjacent to and aligned with the inner member 120 of theactuation part 100. The elongate, flexible portion 101 may furthercomprise a protective outer member 150 to surround the inner member 120,the electrically-conductive conduits 130, the electrodes 112 and thepolymer electrolyte layer 139. The protective outer member 150 isadapted for low-friction sliding engagement with the interior wall of alumen or other bodily passage into which the actuation part 100 of themedical device 10 may be introduced. In an embodiment of amicro-catheter of the medical device 10, the bore 140 provides a passagethrough which a surgical instrument such as, for example, an effector, acutting implement, an imaging device (camera), a light source, a stint,a stint retriever or some other manipulatable surgical instrument can bepassed and/or controlled by the user during surgery. Alternately, thebore 140 may form a fluid passage through which a drug, a radiationsource or other material can be injected for precise placement in thebody having the lumen or bodily passage. Although FIG. 7 illustrates anempty bore 140 in the elongate, flexible portion 101 of the actuationpart 100, this bore 140 is intended for multiple uses. It will befurther understood that a surgical instrument positioned, controlled orintroduced through the bore 140 of the actuation part 100 may beconnected to an effector, instrument, tool or other implement disposedadjacent to the bendable portion 100. It will be further understood thatother devices for positioning a wire or other elongate slender deviceinserted into the bore 140 such as those described in relation to FIG. 6may be used to position a wire or other device within the bore 140without impairment of the function of devices used to position theactuation part 100 within the lumen.

FIGS. 8A and 8B together provide an exploded perspective view of anembodiment of a medical device 10. The medical device 10 herein may be amicro-catheter with an interior bore 140 (e.g., FIGS. 2-4B) or aguidewire without the interior bore 140 (e.g., FIG. 29 ).

FIG. 8A is a perspective view of an upper case portion 210 of the case200 (see FIG. 1 ) of the embodiment of the medical device 10 of FIG. 1with the upper case portion 210 indicated in dotted lines to betterreveal the components of the medical device 10 disposed therein. In oneembodiment of the medical device 10, the upper case portion 210 may bedisposable because it includes the actuation part 100 that is insertedinto, and contaminated by, the lumen or bodily passage of the patientinto which it is inserted and from which it is later withdrawn. Theupper case portion 210 illustrated in FIG. 8A includes a guide barrel211 through which the distal end 102 of the actuation part 100 passes.The guide barrel 211 obscures an aperture (not shown) in the upper caseportion 210 through which the actuation part 100 advances and withdraws.Similarly, the proximal end 109 of the actuation part 100 may passthrough or may be fixedly disposed in an aperture 115. The proximal end109 of the actuation part 100 may further include threads 113 (FIG. 1 )for being paired with a mating socket or connection associated with asurgical instrument or tool. A cavity 215 within the upper case portion210 may be used to store windings 116 formed in the length of theactuation part 100. The windings 116 of the actuation part 100 do notinclude the bendable portion 110, but do include theelectrically-conductive conduits 130 and the inner member 120 (e.g.,FIG. 7 ), both components of the actuation part 100 that are used tosupply, position and control the components that are part of or adjacentto the bendable portion 110. The upper case portion 210 of FIG. 8Afurther includes a drive assembly 300 including a first rotary drivemember 330 a and an adjacent second rotary drive member 330 b. Theactuation part 100 is shown passing intermediate the first rotary drivemember 330 a and an adjacent second rotary drive member 330 b. It willbe understood that clockwise rotation of the first rotary drive member330 a and counterclockwise rotation of the adjacent second rotary drivemember 330 b will withdraw the actuation part 100 from the lumen orbodily passage of the patient and into the case 200, andcounterclockwise rotation of the first rotary drive member 330 a andclockwise rotation of the adjacent second rotary drive member 330 b willadvance the actuation part 100 from the case 200 and into a lumen orbodily passage of the patient into which the distal end 102 of theactuation part 100 has been introduced.

FIG. 8B is a perspective view of a lower case portion 220 of the case200 (see FIG. 1 ) of the embodiment of the medical device 10 of FIG. 1with the lower case portion 220 indicated in dotted lines to betterreveal the components of the medical device 10 disposed therein. In oneembodiment of the medical device 10 in which the upper case portion 210is disposable, the lower case portion 220 may be adapted for repeatedand use, each use requiring pairing of a decontaminated lower caseportion 220 with a new or refurbished upper case portion 210. The shapeof the lower case portion 220 corresponds to the shape of the upper caseportion 210 of FIG. 8A to facilitate the pairing of the lower caseportion 220 with the upper case portion 210 to provide an assembled case200. The lower case portion 220 of FIG. 8B includes components that havea low risk of contamination and those that are of a sufficient cost thatthey are useful for being refurbished, recycled and/or decontaminatedafter each use.

Components of the medical device 10 that are disposed in or on the lowercase portion 220 are positioned to engage related components of themedical device 10 disposed in or on the upper case portion 210 to enablethe coupling of these related components upon assembly of the upper caseportion 210 of FIG. 8A and the lower case portion 220 of FIG. 8B. Forexample, but not by way of limitation, the drive assembly 300 of theupper case portion 210 of FIG. 8A that engages and moves the flexibleactuation part 100 may also engage a motor 310 through an intermediateworm gear 320. The motor 310 drives the worm gear 320 to controllablyrotate a drive fitting 321 positioned to be received into acorresponding drive socket (not shown) formed in the first rotary drivemember 330 a of the upper case portion 210 shown in FIG. 8A. In theembodiment shown in FIGS. 8A and 8B, an interface device 420 enables thecase 200 of the medical device 10 to receive control signals, forexample, signals to advance or withdraw the actuation part 100 usingdrive assembly 300 or to impart bending to the distal end 102 of theactuation part 100 using the bendable portion 110 from a mastercontroller 500 (FIG. 9 ) used by a surgeon or operator (which includesfor example other operators or users such as but not limited to medicalpractitioners, physicians, surgical technicians, nurses or assistants,veterinarians, etc.).

FIG. 9 is an elevational sectional view of an embodiment of a medicaldevice 10 provided by assembling of the upper case portion 210 and thelower case portion 220 of FIGS. 8A and 8B. The windings 116 of theactuation part 100 of the medical device 10 are stored within the cavity215 of the upper case portion 210 of the case 200. The actuation part100 of the medical device 10 extends from the proximal end 109 throughthe windings 116, to the distal end 102 of the actuation part 100 thatextends beyond the guide barrel 211 of the upper case portion 210. FIG.9 shows the manner in which the drive fitting 321 (see FIG. 8B) engagesa socket (not shown) in the first rotary drive member 330 a whichcooperates with the second rotary drive member 330 b to controllablyadvance and withdraw the actuation part 100 from and back into the case200 of the medical device 10, respectively. Optionally, the upper caseportion 210 includes a cavity wall 214 that separates the cavity 215that houses the windings 116 of the actuation part 100 from the adjacentcavity 213 that houses the first rotary drive member 330 a and thesecond rotary drive member 330 b (FIG. 8A) of the drive assembly 300.The medical device 10 of FIG. 9 further includes the electricalcontroller 400 disposed in the lower case portion 220 and used toreceive command signals from the master controller 500 and to generatecontrol electrical signals to the plurality of electrically-conductiveconduits 130 (FIG. 2 ) within the actuation part 100 to energize theplurality of electrodes 112 (e.g., FIG. 2 ) to bend the bendable portion110 (e.g., FIG. 2 ) of the actuation part 110. The electrical controller400 relays the electrical currents through the interface 402 disposed inthe lower case portion 220 to the current distributor 410 disposed inthe upper case portion 210. The current distributor 410 is the interfacebetween the electrical controller 400 and the actuation part 100 of themedical device 10. The proximal end 109 of the actuation part 100 of themedical device 10 is fixed relative to the upper case portion 210 tomaintain a plurality of electrical feeder wires 411 extending betweenthe current distributor 410 and the stationary proximal end 109 of theactuation part 100. It will be understood that the distributor cavity216 of the upper case portion 210 may be sealed to protect the feederwires 411 and related terminals from contamination sources that mayexist in the adjacent windings 116.

In the embodiment of the medical device of FIG. 9 , the number of theplurality of feeder wires 411 provided to deliver electrical currentfrom the electrical controller 400 to the electrically-conductiveconduits 130 (e.g., FIG. 2 ) will match the number of the plurality ofelectrically-conductive conduits 130. An interface socket 415 may bedisposed intermediate the interface 420 of the lower case portion 220and the current distributor 410 of the upper case portion 210. In oneembodiment, the electrical controller 400 may include a wirelessinterface device 405 that is electrically connected to the electricalcontroller 400 and drive assembly 300 enables the electrical controller400 and drive assembly 300 to wirelessly communicate with the mastercontroller 500.

FIG. 10 is a flowchart illustrating the steps of a method 600 ofperforming surgery on a body of a patient using an embodiment of themedical device 10 illustrated in FIGS. 8A and 8B. The method 600includes a step 610 of assembling the upper case portion 210 and thelower case portion 220 to form a case 200, the step 620 of introducingthe distal end 102 of the actuation part 100 into a lumen of the body,the step 630 of extending the actuation part 100 forward and into thelumen of the patient using the drive assembly 300, the step 640 ofdetecting a branched or bending pathways of the lumen or bodily passagein which the actuation part 100 is disposed using an imaging device, thestep 650 of bending the bendable portion 110 at the distal end 102 ofthe actuation part 100 of the medical device 10 to steer the actuationpart 100 into a desired direction through the branched or bendingpathways observed using an imaging device, and the step 660 of reachingthe surgical site with the distal end 102 of the actuation part 100.

Conventional techniques and methods known in the medical sciences may beused in conjunction with the methods and with the medical device 10. Forexample, but not by way of limitation, the step 640 in FIG. 10 requiresthe surgeon to “detect branched and bending pathways” of the lumen ofthe body in which the actuation part 10 is introduced. Morespecifically, the surgeon or operator performing the method of FIG. 10using the medical device 10 may view images of the lumen or bodilypassage (pathway) in the body along which the distal end 102 of theactuation part 100 of the medical device 10 is pushed forward usingradiography, magnetic resonance imaging, ultrasound, elastography,tactile imaging, photoacoustic imaging, tomography and other imagingtechnologies and devices. It will be understood that an imaging devicecan be present in the room with the patient and that the output of theimaging device can be electrically transmitted to the surgeon oroperator using a hardwired connection, for a surgeon who is nearby, andusing telecommunications, such as but not limited to the Internet orwireless communications, for a surgeon or operator who is remotelylocated.

FIG. 11 is a flowchart illustrating a method 601 of controlling anembodiment of the medical device 10 and, more specifically, of impartinga bend to a bendable portion 110 at the distal end 102 of an actuationpart 100 of an embodiment of the medical device 10 (e.g., amicro-catheter or a guidewire). Referring also to FIGS. 2 and 9 , themethod 601 includes the step 641 of generating a manipulation signalusing the master controller 500 which will be received by the electricalcontroller 400 through the wireless interface device 405, step 642 ofusing the electrical controller 400 to determine the electrical signalsto be applied to one or more of the plurality of electrodes 112 toobtain the desired direction and magnitude of bend of the bendableportion 110 of the distal end 102 of the actuation part 100 of themedical device 10, and step 643 of applying the determined electricalsignals to be conducted over the electrically-conductive conduits 130 toone or more of the plurality of electrodes 112 to obtain the desiredmovement in the distal end 102 of the actuation part 100 of the medicaldevice 10.

FIG. 12 is a modification of the block diagram of FIG. 6 illustratingthe control system structure for an alternative embodiment of themedical device 10 including an actuation part 100 and a case 200 (e.g.,FIG. 1 ). The medical device 10 herein may be a micro-catheter with aninterior bore 140 (e.g., FIGS. 2-4B) or a guidewire without the interiorbore 140 (e.g., FIG. 29 ). The actuation part 100 includes a bendableportion 110 and an elongate, flexible portion 101. The case 200 includesa drive assembly 300 and electrical controller 400, and further includesa sensing member 117. The sensing member 117 is a bendable portionsensor that is electrically connected to the plurality of electrodes 112of the bendable portion 110 to sense changes in the electrical signal ateach of the plurality of electrodes 112. More specifically, the sensingmember 117 is individually electrically connected to each of theplurality of electrodes 112 to monitor changes in the potential at eachof the plurality of electrodes 112. Accordingly, the sensing member 117detects deformation of the bendable portion 110 or the absence thereofbased on changes in potential in each of the plurality of electrodes 112over time.

For example, but not by way of limitation, as the bendable portion 110and the elongate, flexible portion 120 of the actuation part 100 isadvanced forward using the drive assembly 300 of the case 200, thesensing member 117 detects whether the lumen or bodily passage throughwhich the bendable portion 100 of the actuation part 100 is advanced isobstructed or whether there is a bend or obstruction in the lumen orbodily passage that is sufficient to prevent or impair forward movementof the actuation part 100. Also, because an electrical signal is appliedto each of the plurality of electrodes 112 by the electrical controller400, the sensing member 117 may determine whether the intended bendingdeformation corresponding to the plurality of electrical signalsgenerated by the electrical controller 400 has occurred by receivingfeedback about the electrical signal at each of the plurality ofelectrodes 112 and by comparing that feedback to the electrical signalsassigned to each of the plurality of electrodes 112.

The sensing member 117 is electrically connected to each of theelectrically-conductive conduits 130 that supply electrical signals toeach of the electrodes 112. It will be understood that, just as thecharacter and nature of an electrical signal delivered to an energizedelectrode 112 determines the unimpaired deformation imparted to thepolymer electrolyte layer 139 disposed adjacent to an energizedelectrode 112, the actual deformation of the polymer electrolyte layer139 can be compared to the electrical signal delivered to the adjacentelectrodes to determine the direction and magnitude of an external forceacting on the polymer electrolyte layer 139.

FIG. 13 is a graph illustrating variance over time in an electricalcurrent applied to a polymer electrolyte layer 139 of a bendable portion110 of an actuation part 100 of an embodiment of a medical device 10.FIG. 13 is a graph showing a change in electrical signal occurring at anelectrode 112 monitored using the sensing member 117. The solid line ofFIG. 13 indicates the value of a sensed electrical signal at any one ofa plurality of electrodes 112. The dotted line of FIG. 13 indicates thevalue of an electrical signal that is applied to an electrode 112 toproduce a bend in a desired direction and at a desired magnitude asdetermined using the electrical controller 400 and an input signal fromthe master controller 500.

Changes in the electrode potential sensed by the sensing member 117 arecaused by both an electrical signal applied to the plurality ofelectrodes 112 by the electrical controller 400 for bending control, andby external forces. Accordingly, the sensing member 117 may be used todetermine the presence, direction and magnitude of an external forceapplied to the bendable portion 110 by taking into account how theelectrical controller 400 performs bending control. As illustrated inFIG. 13 , an electrical signal is applied to an electrode 112 at a timedesignated as t-i. As a result, the value of the electrical signalsensed by the sensing member 117 increases abruptly at time t-i.Therefore, the sensing member 117 may determine the direction andmagnitude of any external force that may be applied to the bendableportion 110 based on the difference in the electrical signal, or AV,between the sensed value and AV_(t)h, the value applied by theelectrical controller 400.

The sensing member 117 may be configured to determine the directionand/or the magnitude of an applied external force depending on whetherthe difference between the sensed value and the value applied by themaster controller 500 exceeds a preset threshold value, AVth. Forexample, the actuation part 100 may be subjected to a small amount ofexternal force as the distal end 102 is brought into contact with alumen wall or as it encounters sliding friction while being pushedforward along a lumen or bodily passage. Accordingly, it is possible topermit an expected small amount of external force during intraluminalmovement of the actuation part 100 and to detect the application of alarger magnitude external force by determining whether an external forceis applied or not based on a threshold value.

While FIG. 13 illustrates the value applied to the electrode uponbending and the value sensed at the electrode due to a deformation onthe same scale, this is for ease of explanation and these values mayvary in an actual situation, depending on the position of installationand the wire characteristics. In this case, using a method ofcalculation suitable for the wire characteristics, the application of anexternal force can be determined based on the value applied uponbending.

In this exemplary embodiment, an external force is sensed by using aplurality of four electrodes 112 used for bending control, without theaddition of external force sensing electrodes to the bendable portion110. However, this is merely an example, and an external force may besensed using various structures.

FIG. 14 is a cross-sectional view illustrating an alternativedistribution of the plurality of electrodes 112 in a bendable portion110 of an actuation part 100 of an embodiment of a medical device 10.The arrangement of the eight electrodes of the bendable portion 110illustrated in FIG. 14 includes four (motive) electrodes 112 forresponding to electrical signals generated by the electrical controller400 (not shown) and an additional four sensing electrodes 112 e forsensing the deformation of the bendable portion 110 in which the eightelectrodes are together disposed. The embodiment of the bendable portion110 of FIG. 14 includes a polymer electrolyte layer 139 having anexterior wall 137 for disposing the electrodes 112 and 112 e.

FIG. 15 is a cross-sectional view of an alternative configuration for abendable portion 110 of an actuation part 100 of an embodiment of themedical device 10. FIG. 15 illustrates a polymer electrolyte layer 139having an exterior wall 137 for disposing the electrodes 112.Circumferentially intermediate each adjacent pair of electrodes 112resides a strain gauge 114 that measures the strain applied to thebendable portion 110 of the actuation part 100 as a result of internalforces applied by the deformation of the polymer electrolyte layer 139disposed adjacent one or more energized electrodes 112 and externalforces applied to the bendable portion 110 as a result of physicalinteraction with the lumen or bodily passage through which the actuationpart 100 of the medical device 10 is being advanced.

FIG. 16 is a flowchart illustrating a method of using a sensing member117 to monitor the performance of an embodiment of a medical device 10and of determining the impact of an external force on the performance ofthe embodiment of the medical device 10. The medical device 10 hereinmay be a micro-catheter with an interior bore 140 (e.g., FIGS. 2-4B) ora guidewire without the interior bore 140 (e.g., FIG. 29 ). The sensingmember 117 may be used to continuously monitor changes in electricalsignal sensed at the plurality of electrodes 112 of the bendable portion110. For example, the sensed value of the electrical signal may be thepotential of each of the plurality of electrodes 112.

The sensing member 117 may monitor changes in electrical signal inducedby the user's bending. That is, the sensing member 117 receivesinformation about the user's bending from the electrical controller 400or the master controller 500 and the sensing member 117 then monitorschanges in electrical signals induced by bending of the bendable portion110. Then, the sensing member 117 monitors changes in electrical signalinduced by actual bending due to both internal and external forces andcompares that change in the electrical signal to the isolated electricalsignal indicating the intended bending.

When a change in signal (except for a change induced by bending) issensed during monitoring, the sensing member 117 determines whether thechange exceeds a preset threshold value or not, and if so, determinesthat an external force is applied. Furthermore, in this step, thedirection of the external force or the amount of the external force maybe calculated by combining information about changes at the electrodes112.

Once the application of an external force is detected, the step ofinforming the user of this is performed. In this exemplary embodiment,the sensing member 117 may send an external force generation signal tothe master controller 500, and issue an alarm message, an alarm sound,or haptic feedback to the user through the master controller 500. Inthis case, the sensing member 117 may, through the master controller500, advise the user of both the direction and magnitude of an externalforce being applied to the bendable portion 110 and thereby enable theuser to determine how to manipulate the bendable portion 110 foradvancing beyond the obstacle engaging the actuation part 100, as wellas the generation of the external force. It will be understood that ifthe actuation part 100 is advanced through a lumen or bodily passagewith excessive force damage to contacted body tissues may occur. Thecapacity to detect the application of external force to the bendableportion 110 of the actuation part 100 of the medical device 10 enablesthe user to deactivate or slow the drive assembly 300 through the mastercontroller 500.

The embodiments of the medical device 10 illustrated in FIGS. 1, 8A, 8Band 9 include a drive assembly 300 comprising a motor 310, anintermediate worm gear 320 and a drive fitting 321 positioned to bereceived into a corresponding drive socket (not shown in FIG. 8A) formedin the first rotary drive member 330 a of the upper case portion 210shown in FIG. 8A. It will be understood that the first rotary drivemember 330 a and the second rotary drive member 330 b illustrated inFIG. 8B are limited in the amount of surface contact between these drivecomponents and the actuation part 100 engaged thereby. As a result ofthe limited amount of surface contact between the first rotary drivemember 330 a and the second rotary drive member 330 b illustrated inFIG. 8B, on the one hand, and the actuation part 100, on the other hand,the resulting frictional force between the actuation part 100 and thefirst rotary drive member 330 a and the second rotary drive member 330 bare also limited. If the resistance to movement and advance of theactuation part 100 into or through a lumen or bodily passage issufficiently high, then it may become difficult to smoothly andcontrollably move the actuation part 100 to the desired position forperforming a planned surgery in the body.

FIG. 17 illustrates an alternate embodiment of the case 201 portion ofthe medical device 10 for controllably advancing and withdrawing theactuation part 100 of the medical device 10. The medical device 10herein may be a micro-catheter with an interior bore 140 (e.g., FIGS.2-4B) or a guidewire without the interior bore 140 (e.g., FIG. 29 ). Thecase 201 of the embodiment of the medical device 10 illustrated in FIG.17 includes a drive assembly 300 that provides increased contact areabetween the drive members 431 a and 432 a and the actuation part 100and, as a result, provides increased frictional force for moving theactuation part 100 against resistance to movement. A drive assembly 300of the case 201 of FIG. 17 includes a guide barrel 411, a motor 310 a,one or more intermediate worm gears 320 a, and the drive assembly 300 isoperated by the motor 310 a working through the one or more worm gears320 a. Like the case 200 illustrated in FIGS. 8A and 8B, the case 201 ofFIG. 17 includes a case upper portion 211 and a case lower portion 221adapted for engaging and being coupled with the case upper portion 211.The motor 310 a and the one or more worm gears 320 a are disposed in thecase upper portion 211 and a worm gear 320 a is positioned to dispose adrive fitting (not shown in FIG. 17 ) disposed on the bottom of the wormgear 320 a into engagement with an inversely-shaped socket (not shown inFIG. 17 ) on a drive shaft 432 that is a part of the drive assembly 300.The drive assembly 300 includes a pair of drive spools 431 a and 432 athat are positioned one opposing the other on opposite sides of apathway through the case lower portion 221 in which the actuation part100 moves through the case lower portion 221. Drive spool 431 a iscoupled through a first belt 433 to an auxiliary spool 431 b and drivespool 432 a is coupled through a second belt 434 (not shown in FIG. 17—see FIG. 18 ) to an auxiliary spool 432 b (not shown in FIG. 17 —seeFIG. 18 ). The actuation part 100 passes intermediate belts 433 and 434and is engaged by both of the belts 433 and 434. The actuation part 100is controllably pushed forward in the direction of arrow 439 orwithdrawn (in the opposite direction of the arrow 439) by operation ofthe motor 310 a to drive the drive spools 431 a and 432 a. It will beunderstood that the contact area between the belts 433 and 434 and theactuation part 100 is substantially greater in the drive assembly 300 ofthe case 201 of the medical device 10 illustrated in FIG. 17 as comparedto the contact area between the first rotary drive member 330 a and thesecond rotary drive member 330 b of the drive assembly 300 of the case200 of the medical device 10 of FIG. 8A. Optionally, belts 433 and 434,on the one hand, and the mating drive spools 431 a and 432 a, on theother hand, may include a series of grooves (or other recesses) and/orridges (or other protrusions), respectively, to promote non-slipengagement with the actuation part 100. Optionally, a pair of worm gears320 a may be disposed on opposite sides of a motor shaft 409 to evenlydistribute torque from the motor 310 a to the drive spools 431 a and 431b. Optionally, tensioners 431 c may be provided to enable the adjustmentand maintenance of proper tension in the belts 433 and 434. Optionally,the drive spools 431 a and 431 b may together be biased into engagementwith the actuation part 100 to ensure non-slip frictional engagementbetween the belts 433 and 434 and the actuation part 100 to improvecontrollability and prevent slippage. Optionally, as will be seen inFIG. 18 , one of the drive spools 431 a and 431 b may be biased intoengagement with the actuation part 100 for the same purposes.

FIG. 18 is a perspective view of the alternative case 201 of FIG. 17with the guide barrel 411 removed to reveal the positions of thecomponents therein. Drive spools 431 a and 431 b are seen straddling theactuation part 100 of the medical device 10 as they do in the embodimentof FIG. 17 . Additionally, the embodiment of the case 201 of the medicaldevice 10 of FIG. 18 includes a tensioner 437 b disposed on the case 201to move as permitted by a slot 435. The tensioner 437 b shown in FIG. 18is biased into engagement with a belt 434 using one or more springs 438that maintain the tensioner 437 b engaged with the belt 434 to keep thebelt 434 in non-slipping engagement with the drive spool 431 b.

FIG. 19 is a perspective view of an elongate, flexible portion 101 of anactuation part 100 of an embodiment of a medical device 10 with asection of an outer member 150 removed to reveal details of the interiorof the actuation part 100 of this embodiment of the medical device 10.The medical device 10 herein may be a micro-catheter with an interiorbore 140 (e.g., FIGS. 2-4B) or a guidewire without the interior bore 140(e.g., FIG. 29 ). The outer member 150 is shown to the right side ofFIG. 19 but is removed from the left side of FIG. 19 to reveal thebendable portion 110 of the actuation part 100 including the innermember 120, and the electrodes 112 circumferentially distributed about apolymer electrolyte layer 139. Each electrode 112 is connected to anelectrically-conductive conduit 130 that delivers an energizingelectrical signal to one or more selected electrode(s) 112 to actuatethe polymer electrolyte layer 139 to bend. FIG. 19 further illustrates areinforcing mesh 121 comprising a wire or filament that is braided orwound radially intermediate the inner member 120 and the outer member150 to provide enhanced structural rigidity and resistance to axialcompression and enhanced resistance to torsional deformation of theactuation part 100 for improved control and steerability. It will beunderstood that the structure of the reinforcing mesh 121 may vary.Other embodiments of the actuation part 100 of the medical device 10 mayinclude encircling coils of reinforcing wire (not shown) as opposed tobraids or mesh. The material of the reinforcing mesh 121 may include,but is not limited to, stainless steel, tungsten or nylon. In oneembodiment of the actuation part 100 of the medical device 10, theelectrically-conductive conduits 130 through which electrical signalsare delivered to the bendable portion 110 of the actuation part 100comprise a plurality of very slender wires available from, among others,MK Electron Co., Ltd. of Gyeonggy-do, Korea. These wires may have adiameter of 25 pm, or 15 pm or less, and may comprise gold, gold-silveralloy or other highly conductive metals that demonstrate high chemicalstability. These wires may be embedded in an insulating medium and maybe of a multiple-layer braided construction.

FIG. 20 is cross-sectional view of an embodiment of an elongate,flexible portion 101 of an actuation part 100 of an embodiment of amedical device 10. The medical device 10 herein may be a micro-catheterwith an interior bore 140 (e.g., FIGS. 2-4B) or a guidewire without theinterior bore 140 (e.g., FIG. 29 ). It will be understood that theelongate, flexible portion 101 includes an inner member 120 and areinforcing mesh 121. An insulating layer 133 is disposed about thereinforcing mesh to isolate the reinforcing mesh 121 from theelectrically-conductive conduits 130 to prevent electrical shorts. Asshown in FIG. 20 the electrically-conductive conduits 130 are circularin cross-section and are formed within a space defined within theinsulating layer 133 between the outer member 150 and the reinforcingmesh 121. The elongate, flexible portion 101 illustrated in FIG. 20further includes an insulation coating 134 to further insulate theelectrically-conductive conduits 130 from the outer member 150 and alsofrom the reinforcing mesh 121.

FIG. 21 is a cross-sectional view of an alternative embodiment of theelongate, flexible portion 101 of the actuation part 100 of anembodiment of the medical device 10 having an inner member 120, areinforcing mesh 121 and electrically-conductive conduits 130. Themedical device 10 herein may be a micro-catheter with an interior bore140 (e.g., FIGS. 2-4B) or a guidewire without the interior bore 140(e.g., FIG. 29 ). The elongate, flexible portion 101 of FIG. 21illustrates that the electrically-conductive conduits 130 and one ormore lumens 135 around each electrically-conductive conduit 130 aretogether encapsulated or encased within the material of the outer member150. The lumens 135 herein may be placed longitudinally within the outermember 150. Each lumen 135 defines an interior space 135 a passingthrough the outer member 150 and an exterior wall 135 b. Eachelectrically-conductive conduit 130 may be correspondingly placedthrough the each interior space of each lumen 135, so that eachelectrically-conductive conduit 130 can be insulated by the exteriorwall 135 b of each lumen 135 to prevent electrical shorts.

FIG. 22 a cross-sectional view of an alternative embodiment of theelongate, flexible portion 101 of the actuation part 100 of anembodiment of the medical device 10 having an inner member 120, areinforcing mesh 121 and an outer member 150. The medical device 10herein may be a micro-catheter with an interior bore 140 (e.g., FIGS.2-4B) or a guidewire without the interior bore 140 (e.g., FIG. 29 ). Theembodiment of the elongate, flexible portion 101 of FIG. 22 furtherincludes a tubular insulation member 127 surrounding the reinforcingmesh 121 to further insulate the electrically-conductive conduits 130from the reinforcing mesh 121.

FIG. 23 is a modification of the block diagrams of FIGS. 6 and 12illustrating a control system 502 for an alternative embodiment of themedical device 10 including an actuation part 100 and a case 200. FIG.23 illustrates a system for remotely controlling a medical device 10having an actuation part 100 introduced within a lumen or passage of thebody of a patient. The medical device 10 herein may be a micro-catheterwith an interior bore 140 (e.g., FIGS. 2-4B) or a guidewire without theinterior bore 140 (e.g., FIG. 29 ). The system 502 comprises a localcommunication member 501 that remotely communicates with the remotemaster controller 500. The surgeon, operator or user uses the mastercontroller 500 to remotely operate the medical device 10 that includesthe actuation part 100, the drive assembly 300 in the case 200 of themedical device, and the electrically-conductive conduits 130 that carryelectrical signals to the bendable portion 110. FIG. 23 illustrates thatthe surgeon, operator or user may remotely control the medical device 10from a remote location using the master controller 500 and the localcommunication member 501, and that the master controller 500 and thelocal communication member 501 may communicate through telephonicsystems, Bluetooth, wireless 802.1 1 communication and/or the Internet.

In an alternative embodiment of the medical device 10, theelectrically-conductive conduits 130 are embedded in a radially exteriorsurface 122 of the inner member 120, as discussed in connection withFIG. 24 .

FIG. 24 is an enlarged view of a portion of FIG. 5 and illustrates aplurality of four electrically-conductive conduits 130 a, 130 b, 130 cand 130 d disposed within a plurality of four parallel and spaced-apartchannels 123, 124, 125 and 126 formed into the exterior surface 122 ofthe inner member 120. It will be understood that the fourelectrically-conductive conduits 130 a, 130 b, 130 c and 130 d are eachisolated one from the others by the barrier portions 129 of the exteriorsurface 122 disposed intermediate each pair of adjacent channels 123,124, 125 and 126.

While FIGS. 2-5 and 7 illustrate embodiments of the bendable portion 110of the actuation part 100 of the medical device 10, it will beunderstood that other embodiments may be easier to fabricate or mayprovide improved responsiveness to the electrical signals generated tomanipulate and steer the intraluminal the medical device 10 to thetargeted location within a body. The discussion that follows relates toan embodiment of the bendable portion 110 of the actuation part 100 ofthe medical device 10 that provides additional benefits.

FIG. 25 is an enlarged perspective view of an alternative tubularpolymer electrolyte layer 139A that is included in a bendable portion100 of an actuation part 100 of an alternate embodiment of the medicaldevice 10 (e.g., a micro-catheter). FIG. 25 shows a bendable portion 110having a plurality of electrodes 112 circumferentially distributed aboutthe exterior wall 137 of a polymer electrolyte layer 139. The electrodes112 in FIG. 25 are each coupled to an electrically-conductive conduit130 for transmitting one or more electrical signals from an electricalsource (not shown in FIG. 25 ) to the electrodes 112. The bendableportion 110 of FIG. 25 includes electrodes 112 that may extend radiallyfurther from an axis 141 of the bendable portion 110 (in a relaxedcondition) than the exterior wall 137 of the tubular polymer electrolytelayer 139A intermediate adjacent pairs of electrodes 112. Theconfiguration of the bendable portion 110 illustrated in FIG. 25 is theresult of a method for making the bendable portion 110, which isdiscussed in detail below.

The alternate embodiment of the bendable portion 110 illustrated in FIG.25 is made by forming a tubular polymer electrolyte layer 139A from apolymer, such as Nafion®, available from The Chemours Company ofWilmington, Del., USA. The exterior wall 137 of the tubular polymerelectrolyte layer 139A is pre-conditioned by roughening the exteriorwall 137 using an abrasive such as, for example, sandpaper, or by anabrasive process such as, for example, sandblasting, followed bycleaning the roughened exterior wall 137 of the tubular polymerelectrolyte layer 139A using a reducing agent such as, for example, ahydrogen peroxide (H₂O₂) solution and/or a sulfuric acid (H₂SO₄)solution, and de-ionized water. The now-roughened and cleaned exteriorwall 137 of the tubular polymer electrolyte layer 139A is thendeposition-plated with a conductive metal such as, for example,platinum. It will be understood that common methods of depositing asolid coating or layer onto a substrate may be used. In one embodimentof the method, an electroless chemical deposition process is used todeposit platinum onto the roughened and cleaned exterior wall 137 of thetubular polymer electrolyte layer 139A. The roughened and cleanedtubular ionic electroactive polymer 139A is impregnated in a complexplatinum salt solution such as, for example, a solution including[Pt(NH₃)₄]Cl₂, for several hours at about 68° F. (20° C.). Thatimpregnation step is followed by a reduction process using an aqueoussolution containing a reducing agent such as, for example, sodiumborohydride (NaBH₄), during which the platinum ions in the polymer arechemically reduced to metallic form at the exterior wall 137 of thetubular polymer electrolyte layer 139A.

After an additional cleaning with a reducing agent such as, for example,sulfuric acid, and deionized water, the exterior wall 137 of the nowplatinum-coated tubular polymer electrolyte layer 139A may be furtherplated with a thin layer of gold (Au) using a conventionalelectrochemical deposition process to increase the thickness andelectrical conductivity of the presently undivided metal electrodes 112that will be ultimately formed onto the exterior wall 137 of the tubularpolymer electrolyte layer 139A. Following the gold deposition processes,the circumferentially continuous sleeve-shaped platinum and gold-coatedexterior wall 137 of the tubular polymer electrolyte layer 139A can besectored into four circumferentially-distributed and isolated metalelectrodes 112 using a micro-machining process. More specifically, acomputer-controlled milling machine with a micro end-mill tool may beused to mechanically remove a thin layer of platinum-gold material and,optionally, a small portion of the underlying exterior wall 137 of thetubular polymer electrolyte layer 139A at a depth of, for example,twenty to forty (20 to 40) microns. In FIG. 25 , the plurality of milledgrooves 136 indicate where the previously circumferentially continuousplatinum-gold electrode has been sectored into plurality of metalelectrodes 112, each coupled to an electrically-conductive conduit 130.FIG. 25 shows four equally sized and circumferentially distributed metalelectrodes 112 centered 90° apart on the exterior wall 137 of thetubular polymer electrolyte layer 139A. The bendable portion 110illustrated in FIG. 25 can be manipulated by selectively introducingenergizing electrical signals into the metal electrodes 112 by way ofthe conduits 130 to provide actuation. In a final step, the finishedtubular polymer electrolyte layer 139A with sectored platinum-goldelectrodes 112 is cleaned and ion-exchanged into a desired cationic form(typically using lithium ions) by soaking in a metal-salt solution suchas, for example, lithium chloride. During this final soaking process,the hydrogen ions (H+) in the tubular polymer electrolyte layer 139A areexchanged with lithium ions (Li−).

A embodiment of a method of disposing the carbon-based electrodes 112 onthe tubular polymer electrolyte layer 139A is also provided. In oneexample, the bendable portion 110 illustrated, e.g., in FIG. 25 , ismade by forming carbon-based electrodes 112 on a tubular polymerelectrolyte layer 139A from a polymer, such as Nafion® using a reflowprocess. Since the electrode integration by the reflow process involveshigh temperature treatment, the exemplary example provided below hereinis a wet assembly method applicable with thermally stable andnon-volatile electrolytes such as ionic liquids.

In this exemplary example, the tubular polymer electrolyte layer 139A ispreconditioned by roughening its exterior wall 137 using an abrasive(e.g., sandpaper) or by an abrasive process (e.g., sandblasting),followed by being cleaned using a reducing agent, for example, ahydrogen peroxide (H₂O₂) solution and/or a sulfuric acid (H₂SO₄)solution, and de-ionized water, but not limited to this. The roughenedand cleaned tubular polymer electrolyte layer 139A is furtherdeposition-plated with a carbon-based conductive powder, such ascarbide-derived carbon, carbon nanotube, carbon aerogel, graphene, orthe combination thereof.

In this exemplary example, one or more electrolytes are thenincorporated in the cleaned tubular polymer electrolyte layer 139A whichis first dried under vacuum (30 in Hg) at about 100 to about 140° C. forseveral hours to remove humidity. Thereafter, the dried tubular polymerelectrolyte layer 139A is impregnated with an ionic liquid (such asEMI-BF4 or EMI-TFSI, but not limited to this) by soaking in respectiveionic liquid at elevated temperature for several hours.

In this exemplary example, after being ionic liquid-impregnated, a layerof carbon-based electrodes 112 are fabricated directly onto the tubularpolymer electrolyte layer 139A as follows. The conductive powdermaterial of carbide-derived carbon (or other carbon allotrope (e.g.,carbon nanotube, carbon aerogel, graphene) or the mixture thereof, butnot limited to this) is dispersed in a volatile solvent of isopropanol(or the like). In an alternative embodiment, the conductive powder mayfurther comprise fillers such as transition metal oxide powder (such asMn0₂ or RUO2) or metal powder (such as Pt or Au). Ionic polymer (Nafion)dispersion in alcohol (or PVDF) is further added in the above-mentionedconductive powder dispersion for a binder. The mixture is homogenized bya treatment in an ultrasonic bath. The prepared conductive powderdispersion is then directly applied onto the tubular polymer electrolytelayer 139A using a conventional brush or spray coating technique to forma layer of carbon-based electrode 112. Volatile solvents are evaporatedby a mild heating process after the desired thickness of the layer ofcarbon-based electrode 112 is achieved.

The electrical conductivity of the obtained layer of carbon-basedelectrode 112 is often inadequate to ensure proper electromechanicalfunctionality for the ionic electroactive polymer actuator. In thisexemplary example, the electrical conductivity of the obtained layer ofcarbon-based electrode 112 may be increased by further attaching Aumicrowire onto the surface of the obtained layer or by embedding Au wirein the obtained layer. Additionally, Au foil with a thickness of 50-150nm may be rolled around the tubular polymer electrolyte layer 139A toserve as a highly conductive current collector.

Then, in this exemplary example, the layer of carbon-based electrode 112is integrated with the tubular polymer electrolyte layer 139A by areflow process. In this process, the heat-shrink polymer tube such asfluorinated ethylene-propylene (FEP) is fitted over the tubular polymerelectrolyte layer 139A and heated up to a recovery temperature of theheat-shrink material. The supplied heat and applied compressive load bythe heat-shrink tube may cause reflow of the ionic polymer from thetubular polymer electrolyte layer 139A, so that the layer ofcarbon-based electrode 112 and Au foil are thermally bonded with thetubular polymer electrolyte layer 139A. After this reflow process, theheat shrink tube is removed and the layer of carbon-based electrode 112is sectored into four isolated carbon-based electrode sectors 112 usinga micromachining process, where the computer-controlled milling machinewith micro end-mill tool is used to mechanically remove a thin layer ofcarbon-Au composite and the tubular polymer electrolyte layer 139A at adepth of 30-50 microns. This process creates four equally sizedcarbon-based electrode sectors 112 at every 90° on the tubular polymerelectrolyte layer 139A which can be independently controlled byelectrical power to achieve two degrees-of-freedom actuation.

In another example, the bendable portion 110 illustrated, e.g., in FIG.25 , is made by forming carbon-based electrodes 112 on a tubular polymerelectrolyte layer 139A from a polymer, such as Nafion® using a reflowprocess. This example is directed to a dry assembly applicable with bothvolatile (such as aqueous) and non-volatile (ionic liquids)electrolytes. The tubular polymer electrolyte layer 139A (Nafion®,DuPont) is provided and pre-conditioned as described above. To prepare alayer of carbon-based electrodes 112 onto the conditioned the tubularpolymer electrolyte layer 139A, the conductive powder material ofcarbide-derived carbon (or other carbon allotrope, e.g., carbonnanotube, carbon aerogel, graphene, or mixtures thereof) is dispersed ina volatile solvent of isopropanol (or the like). In some embodiments,the conductive powder may further comprise transition metal oxidepowders (such as Mn0₂ or Ru0₂, but not limited to this) or metal powder(Pt or Au, but not limited to this).

In this exemplary example, ionic polymer (Nafion) dispersion in alcohol(or PVDF) is further added in the conductive material dispersion for abinder. The mixture is homogenized by a treatment in an ultrasonic bath.Next, the prepared conductive powder dispersion is directly applied ontothe tubular polymer electrolyte layer 139A using a brush or spraycoating technique after being ionic liquid-impregnated. Volatilesolvents are evaporated by a mild heating process until the desiredthickness of the layer of carbon-based electrodes 112 is achieved.

The electrical conductivity of the obtained layer is often inadequate toensure proper electromechanical functionality for the ionicelectroactive polymer actuator. In terms of this, in this exemplaryexample, the electrical conductivity of the obtained layer ofcarbon-based electrodes 112 may be increased by attaching Au microwireonto the surface of the layer of carbon-based electrodes 112 or byembedding Au wire in the layer of carbon-based electrodes 112. Then, thelayer of carbon-based electrodes 112 is integrated with the tubularpolymer electrolyte layer 139A by a reflow process. In this process, theheat-shrink polymer tube such as fluorinated ethylene-propylene (FEP) isfitted over the tubular polymer electrolyte layer 139A and heated up toa recovery temperature of the heat-shrink material. The supplied heatand applied compressive load by the heat-shrink tube cause reflow of theionic polymer, so that the layer of carbon-based electrodes 112 and Aufoil are thermally bond with the tubular polymer electrolyte layer 139A.After reflow process, the heat shrink tube is removed. Additionally, theelectrical conductivity of the layer of carbon-based electrodes 112 maybe further increased by applying a thin layer of Pt thereon using theelectroless chemical deposition and subsequent electrochemicaldeposition of Au.

Then, in this exemplary example, the obtained layer of carbon-basedelectrodes 112 is sectored into four isolated electrode sectors 112using a micromachining process, where the computer-controlled millingmachine with micro end-mill tool is used to mechanically remove a thinlayer of carbon-based electrodes 112 and the tubular polymer electrolytelayer 139A at a depth of 30-50 microns. This process thus creates fourequally sized electrode sectors 112 at every 90° on the surface of thetubular polymer electrolyte layer 139A which can be independentlycontrolled by electrical power to achieve two degrees-of-freedomactuation.

Finally, in this exemplary example, the electrolyte is incorporated inthe cleaned tubular polymer electrolyte membrane layer 139A. First, thetubular polymer electrolyte layer 139A is dried under vacuum (30 in Hg)at 100-140° C. for several hours to remove humidity. Thereafter, thedried tubular polymer electrolyte layer 139A is impregnated with anionic liquid (such as EMI-BF4 or EMI-TFSI) by soaking in respectiveionic liquid at elevated temperature for several hours.

In another embodiment, the flexible and elongate portion 101 of themedical device 10 (see FIGS. 1, 7, 8A, 8B, 17, 19 and 25 ) used to movethe bendable portion 110 as described above can be formed usingconventional processes known in the art. Alternately, an inner member120 may comprise a polytetrafluoroethylene (PTFE) material, areinforcing mesh 121 (see FIG. 19 ), which may be a braided wire or acoiled wire, and an outer member 150 are placed over a slender rod or apin to be used as a mandrel. Four electrically-conductive conduits 130,which may comprise gold wires having a small diameter of, for example,25 pm, are aligned with and secured along the length of the insulatingtube using an adhesive such as, for example, an epoxy adhesive or, morespecifically, a photo-activated (for example, such as a ultravioletlight-activated) adhesive. An outer member 150, which functions as asheath or a jacket comprising a resilient material such as, for example,PEBAX®, available from Arkema of Colombes, France, is sheathed overinner member 120 and the electrically-conductive conduits 130 adheredthereto. The inner member 120, the reinforcing mesh 121 (which may be,for example, braided wire or coiled wire), the tubular insulation member127 and the outer member 150 may be assembled using a reflow process.For subsequent coupling with the polymer electrolyte layer 139, theinner member 120 is left longer in length than the outer member 150,resulting in an extended portion of the inner member 120 that extendsfurther beyond the distal end of the outer member 150. A polymerelectrolyte layer 139 is placed over the extended portion of the innermember 120 and moved proximal to the distal end of the outer member 150and the electrically-conductive conduits 112 are connected to the fourelectrodes 112 formed onto the exterior of the polymer electrolyte layer139 using epoxy, followed by a reflow process.

The polymer electrolyte layer 139 may have an outer diameter of, forexample, one millimeter (1 mm), a length of, for example, twentymillimeters (20 mm). It will be understood that the size may vary withthe intended application. The polymer electrolyte layer 139 may beclamped in a vertical cantilever configuration using a custom-madeconnector clamp with four spring-loaded prong contacts that attach toeach electrode 112 formed on the polymer electrolyte layer 139 (see FIG.25 ). The free-length of the polymer electrolyte layer 139 may be up toeighteen millimeters (18 mm) or more. Electrical wires from the clampmay be connected to a custom-made controller device. A digitalmicroscope camera such as, for example, a Plugable® USB 2.0, may be usedto record images of the actuation of the polymer electrolyte layer 139.

In one embodiment of the medical device 10 (e.g., a micro-catheter), thebore 140 of the inner member 120 can be used to guide an inserted centerwire 270 having an effector attached thereto to a predetermined positionwithin a lumen of the body. For example, but not by way of limitation,FIG. 26 illustrates a distal end 102 of an actuation part 100,comprising: a radially interior bore 140, at least one polymerelectrolyte layer 139, the polymer electrolyte layer 139 securedadjacent to the distal end 102 of the actuation part 100 in alignmentwith the inner member 120. A plurality of electrodes 112 arecircumferentially distributed about the at least one polymer electrolytelayer 139 and connected to a source of electrical current through aplurality of electrically-conductive conduits 130, each having aproximal end coupled to the source of electrical current (not shown) anda distal end coupled to at least one of the plurality of electrodes 112.An elongate and flexible center wire 270 having a proximal end (notshown), a distal end 272 and a diameter 279 therebetween that is smallerthan the diameter of the bore 140 of the inner member 120 of theactuation part 100 is introduced into the bore 140 of the actuation part100 with a spring member 271 connected to the distal end 272 of thecenter wire 270. The spring member 271 is radially compressed to thestate illustrated in FIG. 26 to enable it to be introduced, whileconnected to the distal end 272 of the center wire 270, into the bore140 of the actuation part 100. The spring member 271 and the center wire270 are pushed through the bore 140 of the actuation part 100 until thespring member 271 is in the bore 140 of the bendable portion 110 at thedistal end 102 of the actuation part 100 to position the distal end 272of the center wire 270 adjacent to the distal end 102 of the actuationpart 110. The spring member 271 is a radially compressible and resilientspring member 271 coupled to the distal end 272 of the center wire 270.The spring member 271 is sized for exceeding the diameter 279 of thebore 140 of the actuation part 100 in an expanded configuration and forfitting within and being positioned in the bore 140 of the actuationpart 100 by the center wire 270 in a radially compressed configurationas shown in FIG. 26 . The center wire 270 can be used to advance, in thedirection of arrow 291, and to position the spring member 271immediately adjacent to the distal end 102 of the actuation part 100with the actuation part 100 disposed within or immediately adjacent toan obstruction 293 in a blood vessel (lumen) 290 into which theactuation part 100 is introduced.

The spring member 271 can be expanded to engage and grip the obstruction293 in the blood vessel 290 by retracting the actuation part 100 in thedirection of arrow 292 while maintaining the center wire 270 stationaryto cause the actuation part 100 to be withdrawn from a surroundingposition about the spring member 271, thereby causing the spring member271 to be released from the radially compressed configuration to theexpanded configuration shown in FIG. 27 . FIG. 27 illustrates how theobstruction 293 is gripped by the expanded spring member 271, therebyallowing the obstruction 293 to be retrieved in the direction of thearrow 292 from the blood vessel 290 by retrieving the center wire 270and the actuation part 100 together from the blood vessel 290.

In one embodiment, the spring member 271 is a coil spring having aplurality of coils 296 in a series as shown in FIG. 26 . In anotherembodiment, the spring member 271 includes a plurality of corrugated orsinusoidally shaped wires 294 as shown in FIG. 28 , each coupled at theapexes of the waves or peaks 295 to the apexes of the waves or peaks 295of an adjacent wire 294 to form a generally tubular or cylindricallyshaped spring assembly 271A, as shown in FIG. 28 . It will be understoodthat expandable spring elements of this type generally elongate as theyradially expand from a radially compressed configuration to a radiallyexpanded configuration.

FIG. 29 is a perspective view of the elongate, flexible portion 101 anda bendable portion 110 disposed at the distal end 102 of the actuationpart 100 of another embodiment of the medical device 10 of FIG. 1 .Unlike a micro-catheter (e.g., the medical device shown in FIGS. 2-4B),FIG. 29 illustrates a medical device 10 without an interior bore thatmay, for example, be a guidewire. The bendable portion 110 of theactuation part 100 includes an ionic electroactive polymer actuatorcomprising a polymer electrolyte body 139B disposed adjacent to theinner member 120 of the elongate, flexible portion 101 and centrally toan angularly-distributed plurality of energizable electrodes 112. Eachof the plurality of electrodes 112 that surrounds the exterior wall 138of the polymer electrolyte body 1398 is connected to a distal end 131 ofan electrically-conductive conduit 130 through which an electricalsignal or current may be supplied to the connected electrode 112. Toincrease the function of the guidewire (e.g., support, steering,tracking, visibility, tactile feedback, lubricity, and/or trackability),it will be understood that the elongate, flexible portion 101 mayoptionally further comprise a protective outer member (not shown, suchas a cover and/or coating) to surround the inner member 120 while ahelical coil may be optionally further covered over the protective outermember. The bendable portion 110 of FIG. 29 is illustrated in thestraight mode, which can be selectively and controllably deformed to abent mode by selective energization of one or more of the plurality ofelectrodes 112, as explained above.

FIG. 30 is the perspective view of the bendable portion 110 at thedistal end 102 of the actuation part 100 of FIG. 29 illustrating thedeformed or bending mode. The bendable portion 110 of the actuation part100 of the medical device 10 is illustrated as having been actuated fromthe straight mode shown in FIG. 29 to the deformed or bent mode of FIG.30 through the selective application of electrical signals to selectedelectrodes 112 to deform the polymer electrolyte body 1398. Theenergization of selected electrodes 112 causes the bendable portion 110to be deformed from the straight mode to the bent mode by application ofan external force indicated by arrow 118. It will be understood that themedical device 10 in FIGS. 29 and 30 , as a guidewire, may be used tonavigate vessels to reach a lesion or vessel segment. Once the bendableportion 110 of the medical device 10 arrives at its destination, it actsas a guide so that larger catheters having a bore for passing throughthe guidewire can rapidly follow for easier delivery to the treatmentsite.

In some embodiments a medical device 10 comprises an elongate flexibleportion 101 that comprises an outer tubular layer; an inner tubularlayer, wherein a space is formed between the outer tubular layer and theinner tubular layer; a support layer positioned within the space,wherein the support layer comprises: a braided wire, a coil or thecombination thereof being covered on an outer surface of the innertubular layer; a bendable portion 110 provided at a distal end 102 ofthe elongate flexible portion 101, comprising an ionic electroactivepolymer layer, that is bendable in a desired direction in response to anapplied electrical signal, wherein the ionic electroactive polymer layercomprises: an ionomer tubular layer comprising an electrolyte and aplurality of electrodes placed in contact with the ionomer tubularlayer; and a transmitting member which comprises a plurality of wiresrespectively arranged along the space of the flexible elongate memberand electrically connecting the electrodes. In some embodiments thewires further comprise an insulating layer.

In some embodiments a medical device comprises a flexible elongatedmember; and a bending member provided at a distal end of the flexibleelongated member, made from an electroactive polymer, and bendable in adesired direction in response to an applied electrical signal, whereinthe bending member comprises a main body made of an ionic electroactivepolymer and a plurality of electrodes placed in contact with the mainbody. In some embodiments the outer surfaces of the flexible elongatedmember and the bending member are coated with a hydrophilic material.

In some embodiments the bendable portion 110 further comprises anencapsulation layer covering the bendable portion 110. In someembodiments the flexible inner member 120 and the bendable portion 110are coated with a hydrophilic material and/or the bendable portion 110further comprises a tubular insulation member 127 between thereinforcing mesh and electrically-conducting conduit 130. In someembodiments the outer tubular member further comprises a plurality ofinsulation layers. In some embodiments each wire passes through eachinsulation layer respectively. In some embodiments, the electrodes areselected from the group consisting of Pt electrodes, Au electrodes,carbon electrodes, or the combination thereof. In some embodiments thecarbon electrodes are selected from the group consisting ofcarbide-derived carbon, carbon nanotube, graphene, a composite ofcarbide-derived carbon and ionomer, and a composite of carbon nanotubeand ionomer. In some embodiments, the electrodes are symmetricallyarranged along the circumference of the ionic electroactive polymerlayer and in some embodiments there are four electrodes.

In some embodiments the device further comprises an electricalcontroller that transmits electrical signals through theelectrically-conducting conduit 130 to the electrodes and inducingbending of the bendable portion 110. In some embodiments the electricalcontroller is configured to generate electrical signals in response touser manipulation such that the bendable portion 110 responds to usermanipulation. In some embodiments the medical device is a catheter or aguide wire.

In some embodiments, the device further comprises a drive assemblyconfigured to move the flexible inner member 120 lengthwise. In someembodiments the drive assembly is configured to come into partialcontact with the surface of the flexible inner member 120 using afriction-based mechanism that acts between the drive assembly and thesurface.

In some embodiments, the drive assembly comprises at least a pair ofrotary drive members 330 a, 330 b and a motor 310 that operates therotary drive members 330 a, 330 b. The flexible inner member 120 isarranged to pass between the pair of rotary drive members 330 a, 330 band is moved along lengthwise with the operation of the rotary drivemembers 330 a, 330 b.

In some embodiments the pair of rotary drive members 330 a, 330 bcomprise spools rotatably placed, and the flexible inner member 120 isplaced to be movable between the pair of spools by the rotation of thespools. In some embodiments the drive system comprises a pair of beltsthat are arranged on either side of the flexible inner member 120, andthe flexible inner member 120 is placed to be movable between the pairof belts by the operation of the belts.

In some embodiments the medical device further comprises: a upper caseportion 210 that accommodates the flexible inner member 120; and a lowercase portion 210 that is detachable from the upper case portion 210,wherein some or all parts of the drive assembly and the electricalcontrol member are placed in the lower case portion 210. In someembodiments, the moving parts are arranged in the upper case portion210. In some embodiments the drive assembly further comprises: a currentdistributor 410 electrically connecting the wires and being inside theupper case portion 210; an interlocking part for transmitting drivingforce from the motor 310 to the moving parts, being provided in thelower case portion 210; and an interface device 420 being connected tothe electrical controller and provided in the lower case portion 210. Insome embodiments the upper case portion 210 and the lower case portion210 are fastened together, the worm gear 320 of the lower case portion210 is connected to the moving parts of the upper case portion 210 totransmit the driving force, and the interface device 420 of the lowercase portion 210 is connected to the current distributor 410 of theupper case portion 210 to transmit electrical signals from theelectrical controller to the wires. Some embodiments further comprise asensing member that senses an electrical signal at the bendable portion110 when a deformation occurs to the bending member. In some embodimentsthe bendable sensing member 117 is configured to determine whether anexternal force is applied to the bendable portion 110 or not,considering an electrical signal generated by bending control from theelectrical control member, out of electrical signals sensed at thebending member. Some embodiments further comprise a master controllerthat remotely instructs the electrical controller and the driveassembly. In some embodiments the medical device is a catheter in whichthe flexible inner member 120 and the bendable portion 110 have aconduit inside and in some embodiments the medical device is a guidewire. In some embodiments the bendable portion 110 further comprises anencapsulation layer being covered the bending member. In someembodiments the outer surfaces of the flexible inner member 120 and thebendable portion 110 are coated with a hydrophilic material. In someembodiments the medical device the wires further comprise an insulationlayer. In some embodiments the bendable portion 110 further comprises atubular insulation member 127 between the reinforcing mesh andelectrically-conducting conduit 130. In some embodiments the outertubular member further comprises a plurality of insulation layers. Insome embodiments each wire passes through each insulation layerrespectively. In some embodiments the electrodes are Pt electrodes, Auelectrodes, carbon electrodes or the combination thereof. In someembodiments the ionic electroactive polymer layer further comprisescarbon-based electrodes consisting of carbide-derived carbon, carbonnanotube, graphene, a composite of carbide-derived carbon and ionomer,and a composite of carbon nanotube and ionomer. In some embodiments theelectrodes are symmetrically arranged along the circumference of theionic electroactive polymer layer. In some embodiments there are fourelectrodes.

In some embodiments the electrical controller is configured to generateelectrical signals, and the drive assembly is configured to move theflexible inner member 120 in response to user manipulation.

In some embodiments a system for remotely controlling the positioning ofa medical device within the body of a patient comprises: a remotecontrol member that comprises a master controller that remotelyinstructs the medical device to be positioned within the body of thepatient; and a local communication member configured to communicate acontrol signal between the remote control member and the medical device.In some embodiments the communication member wirelessly transmitsinformation using Bluetooth or wireless 802.1 1 communication over theinternet. In some embodiments the system drive assembly is configured tocome into partial contact with the surface of the flexible inner member120 and move the flexible inner member 120 based on a friction-basedmechanism acting between the drive assembly and the surface. In someembodiments the system drive assembly comprises at least a pair ofrotary drive members 330 a, 330 b and a motor 310 that operates therotary drive members 330 a, 330 b, and the flexible inner member 120 isarranged to pass through between the pair of rotary drive members 330 a,330 b and moves lengthwise along with the operation of the rotary drivemembers 330 a, 330 b.

In some embodiments of the system the pair of rotary drive members 330a, 330 b comprises a pair of spools that are rotatably placed, and theflexible inner member 120 is placed to be movable between the pair ofspools by the rotation of the spools. In some embodiments the system thepair of rotary drive members 330 a, 330 b comprises a pair of belts thatare arranged on either side of the flexible inner member 120, and theflexible inner member 120 is placed to be movable between the pair ofbelts by the operation of the belts. In some embodiments the systemfurther comprises an upper case portion 210 that accommodates a tubularflexible inner member 120; and a lower case portion 210 that is placedto be detachable from the upper case portion 210, wherein some or allparts of the drive assembly and the electrical controller are placed inthe lower case portion 210. In some embodiments the system the rotarydrive members 330 a, 330 b are arranged in the upper case portion 210.In some embodiments the system the drive assembly further comprises: acurrent distributor 410 electrically connecting the wires and beinginside the upper case portion 210; a worm gear 320 for transmittingdriving force from the motor 310 to the moving parts, being provided inthe lower case portion 210; and a interface device 420 being connectedto the electrical controller and provided in the seconding module. Insome embodiments of the system the upper case portion 210 and the lowercase portion 210 are fastened together, the worm gear 320 of the lowercase portion 210 is connected to the rotary drive members 330 a, 330 bof the upper case portion 210 to transmit the driving force, and theinterface device 420 of the lower case portion 210 is connected to thecurrent distributor 410 of the upper case portion 210 to transmitelectrical signals from the electrical controller/processor to thewires.

In some embodiments the system further comprises a sensing member 117that senses an electrical signal at the bendable portion 110 when adeformation occurs to the bending member. In some embodiments thesensing member 117 is configured to determine whether an external forceis applied to the bendable portion 110 or not, considering an electricalsignal generated by bending control from the electrical control member,out of electrical signals sensed at the bending member. In someembodiments the system further comprises a master controller thatremotely instructs the electrical controller and the drive assembly. Insome embodiments of the system the medical device is a catheter in whichthe flexible inner member 120 and the bendable portion 110 have aconduit inside. In some embodiments the medical device is a guide wire.In some embodiments of the system the bendable portion 110 furthercomprises an encapsulation layer being covered the bending member. Insome embodiments of the system the outer surfaces of the flexible innermember 120 and the bendable portion 110 are coated with a hydrophilicmaterial. In some embodiments the system the wires further comprise aninsulation layer. In some embodiments of the system the bendable portion110 further comprises a tubular insulation member 127 between thereinforcing mesh and electrically-conducting conduit 130. In someembodiments of the system the outer tubular member further comprises aplurality of insulation layers. In some embodiments of the system eachwire passes through each insulation layer respectively. In someembodiments of the system the electrodes are Pt electrodes, Auelectrodes, carbon electrodes or the combination thereof. In someembodiments of the system the ionic electroactive polymer layer furthercomprises carbon-based electrodes consisting of carbide-derived carbon,carbon nanotube, graphene, a composite of carbide-derived carbon andionomer, and a composite of carbon nanotube and ionomer. In someembodiments of the system the electrodes are symmetrically arrangedalong the circumference of the ionic electroactive polymer layer. Insome embodiments of the system there are four electrodes. In someembodiments of the system the electrical controller is configured togenerate electrical signals, and the drive assembly is configured tomove the flexible inner member 120 in response to user manipulation. Insome embodiments, the inner member 120 is tubular. In some embodimentsthe ionomer tubular layer comprising an electrolyte is a polymerelectrolyte layer 139. In some embodiments the ionic electroactivepolymer layer comprises a polymer electrolyte layer 139 and a pluralityof electrodes 112.

Certain embodiments include methods for preparing the bendable portion110 of a device comprising the steps of: providing a polymer electrolytelayer 139 and a mandrel against an inner surface of the ionomer tube;forming a carbon electrode layer on an outer surface of the polymerelectrolyte layer 139, wherein a mixture of a carbon-based conductivepower is applied onto the outer surface of the polymer electrolyte layer139; attaching an electrically-conducting conduit 130 on the carbonelectrode layer, wherein the electrically-conducting conduit 130comprises a plurality of wires respectively being electrically connectedto the carbon electrode layer; providing a heat-shrink tubular layercovered around the carbon electrode layer and the polymer electrolytelayer 139; heating the heat-shrink polymer to cause reflow of the ionicelectroactive polymer from the polymer electrolyte layer 139, so thatthe carbon electrode layer and the polymer electrolyte layer 139 arethermally bonded; and removing the heat-shrink tubular layer and themandrel to form the bending member.

In some embodiments the method further comprises the steps of: forming aplatinum layer on the carbon electrode layer; forming a gold layer onthe platinum layer; micromachining the carbon electrode layer to besectored into a plurality of carbon electrodes; and incorporatingelectrolytes into the bending member, wherein the bendable portion 110is dried to remove humidity and impregnated with an ionic liquid. Insome embodiments the platinum layer is disposed on the carbon electrodelayer using electroless chemical deposition. In some embodiments thegold layer is disposed on the platinum layer using electrochemicaldeposition. In some embodiments a computer-controlled milling machinewith a micro end-mill tool is used to mechanically remove a thin layerfrom the carbon electrode layer and the polymer electrolyte layer 139 ata predetermined depth. In some embodiments the predetermined depth isabout 30 to about 50 microns.

In some embodiments the method for preparing a bendable portion 110 of amedical device, comprises steps of: providing a mandrel against an outersurface of a polymer electrolyte layer 139 comprising at least a ionicelectroactive polymer; incorporating electrolytes into the bendingmember, wherein the bendable portion 110 is dried to remove humidity andimpregnated with an ionic liquid; forming a carbon electrode layer onthe polymer electrolyte layer 139, wherein at least a carbon-basedconductive power is dispersed in a volatile solvent to form an a mixtureof the carbon electrode and the mixture is applied onto the polymerelectrolyte layer 139 to form a carbon electrode layer; attaching anelectrically-conducting conduit 130 on the carbon electrode layer,wherein the electrically-conducting conduit 130 comprises a plurality ofwires respectively being electrically connected to the carbon electrodelayer; disposing a heat-shrink polymer around the carbon electrode layerand the polymer electrolyte layer 139; heating the heat-shrink polymer,the carbon electrode layer and the polymer electrolyte layer 139 tocause reflow of the ionic electroactive polymer from the polymerelectrolyte layer 139, whereby the carbon electrode and the polymerelectrolyte layer 139 are thermally bonded; and removing the first heatshrink material and the mandrel to form the bending member. Someembodiments further comprise the steps of: micromachining the carbonelectrode layer to be sectored into a plurality of carbon electrodes.While in other embodiments a computer-controlled milling machine withmicro end-mill tool is used to mechanically remove a thin layer from thecarbon electrode layer and the polymer electrolyte layer 139 at apredetermined depth, for example a predetermined depth is about 30 toabout 50 microns.

In some embodiments the bendable portion 110 is dried to removehumidity, and then is impregnated with an ionic liquid. In someembodiments the drying occurs under vacuum at about 100 to about 140° C.In some embodiments the ionic liquid is 1-ethyl-3-methylimidazoliumtetrafluoroborate (EMI-BF4), 1-Ethyl-3-methylimidazoliumbis(trifluoromethylsulfonyl)imide (EMI-TFSI) or a combination thereof.In some embodiments the ionic electroactive polymer is an ionicpolymer-metal composite (IPMC). In some embodiments the ionicpolymer-metal composite (IPMC) is Nafion. In some embodiments of themethod the carbon-based conductive powder is selected fromcarbide-derived carbon, carbon nanotube, carbon aerogel, graphene, orthe combination thereof. In some embodiments the carbon-based conductivepowder further comprises: transition metal oxide powder or metal powderor the combination thereof. In some embodiments the transition metaloxide powder comprises: Mn0₂, Ru0₂ or the combination thereof. In someembodiments the metal powder comprises: Pt, Au or the combinationthereof. In some embodiments attaching a electrically-conducting conduit130 on the carbon electrode layer further comprises a step of attachinga gold foil layer covered the polymer electrolyte layer 139.

In some embodiments of the method at least one carbon-based conductivepowder is dispersed in a volatile solvent to form a mixture that isapplied onto outer surface of the polymer electrolyte layer 139 to forma carbon electrode layer. In some embodiments the mixture is appliedonto the polymer electrolyte layer 139 using brush coating or spraycoating to form a carbon electrode layer. In some embodiments thevolatile solvent is isopropanol. In some embodiments the polymerelectrolyte layer 139 is pretreated to roughen and clean the outersurface thereof. In some embodiments the outer surface of the polymerelectrolyte layer 139 is roughened by a mechanical treatment, such as,but not limited to sandpapering or sandblasting. In some embodimentswherein the outer surface of the polymer electrolyte layer 139 iscleaned with hydrogen peroxide (H₂O₂), sulfuric acid (H₂S0₄) solutions,and de-ionized (DI) water.

Some embodiments provide a method for preparing a polymer electrolytelayer 139 in tubular shape for a bendable portion 110 of a device,comprising steps of: providing a liquid dispersion of a base materialthat is selected from the group consisting of ionic polymer,fluoropolymer and intrinsically conductive polymer; casting the liquiddispersion on a substrate; forming a polymer film on the substrate bycuring the liquid dispersion; providing a mandrel, wherein the mandrelis further rolled around with the polymer film being removed from thesubstrate; and providing a heat-shrink tube to cover the rolled polymerfilm around the mandrel, and heating the heat-shrink tube to causereflow of the rolled polymer film to form a polymer electrolyte layer139. In some embodiments the ionic polymer comprises Nafion or Flemion.In some embodiments the fluoropolymer comprises Poly[(vinylidenedifluoride)-co-(chlorotrifluoroethylene) (PVDF) or the co-polymerthereof. In some embodiments the co-polymer comprises Poly(vinylidenedifluoride-co-chlorotrifluoroethylene) (P(VDF-CTFE)) or Poly(vinylidenefluoride-co-hexafluoropropylene) (P(VDF-HFP)).

In some embodiments the intrinsically conductive polymer comprises:polyaniline (PANI), polypyrrole (Ppy), poly(3,4-ethylenedioxythiophene)(PEDOT), or poly(p-phenylene sulfide) (PPS). In some embodiments thebendable portion 110 is an electroactive polymer actuator. In someembodiments the medical device is a catheter. In some embodiments thesubstrate is a PTFE plate or a glass plate. In some embodiments theheat-shrink tube is a fluorinated ethylene-propylene (FEP) tube. In someembodiments the heat-shrink tube is heated at a temperature of 200 to230° C.

It is to be noted that various modifications or alterations can be madeto the above-described exemplary embodiments of the invention withoutdeparting from the technical features of the invention as defined in theappended claims.

What is claimed is:
 1. A method for preparing an ionic electroactivepolymer actuator of a medical device in tubular shape, comprising:providing a polymer electrolyte layer having an exterior wall; providinga mixture of a carbon-based conductive powder in a volatile solvent;providing a plurality of electrically-conductive conduits, each having aproximal end and a distal end; disposing the mixture on the exteriorwall of the polymer electrolyte layer to form a carbon electrode layerthereon; contacting the distal end of each electrically-conductiveconduit to the carbon electrode layer; providing a heat-shrink tube;covering the polymer electrolyte layer and the carbon electrode layerthereon with the heat-shrink tube; and heating the heat-shrink tube tocause reflow of the polymer electrolyte layer to form the ionicelectroactive polymer actuator.
 2. The method of claim 1, wherein thepolymer electrolyte layer is further impregnated with an electrolyte. 3.The method of claim 1, wherein the electrolyte comprises an ionic liquidincluding one or more of 1-ethyl-3-methylimidazolium tetrafluoroborate(EMI-BF4), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide(EMI-TFSI), or the combination thereof.
 4. The method of claim 1,wherein a portion of the carbon electrode layer is further covered withone or more metal layers.
 5. The method of claim 1, wherein afterheating the heat-shrink tube, the carbon electrode layer is furthermicromachined to form a plurality of electrodes.
 6. The method of claim1, wherein the carbon-based conductive powder comprises carbide-derivedcarbon, carbon nanotube, carbon aerogel, graphene, or a combinationthereof.
 7. The method of claim 1, wherein the carbon-based conductivepowder further comprises transition metal oxide powder, metal powder, ora combination thereof.
 8. The method of claim 1, wherein the mixture isdisposed on the exterior wall of the polymer electrolyte layer using abrush coating or spray coating.